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ANALYSIS OF STORMWATER MANAGEMENT SYSTEMS IN WUHAN, CHINA By RONG SHENG A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN ARCHITECTURAL STUDIES UNIVERSITY OF FLORIDA 2015
Â© 2015 Rong Sheng
To my parents, and my dear friend s
4 ACKNOWLEDGMENTS Firstly, I would like to thank my parents for their full support for my study here in U niversity of Florida . Secondly, I would like to thank my committee members, Professor Nawari Nawari and Professor William Tilson for their invaluable advice, encouragement and their tireless efforts made throughout the writing of this thesis. Add itionally, I would also like to thank Mr. Michael Kung for his help in resolving technical issues during the course. Next, I would like to thank my friends, fellow clas smates and neighbor s for their accompany and support throughout the time in America . Las tly, I would like to thank the University of Florida and the entire College of Design, Construction and Planning for the uniquely international experience in studying together with all the people around world in different locations and time zones .
5 TABLE OF CONTENTS ACKNOWLEDGMENTS ................................ ................................ ................................ .............. 4 TABLE OF CONTENTS ................................ ................................ ................................ ................ 5 LIST OF TABLES ................................ ................................ ................................ .......................... 7 LIST OF FIGURES ................................ ................................ ................................ ........................ 8 LIST OF OBJECTS ................................ ................................ ................................ ........................ 9 LIST OF ABBREVIATION S ................................ ................................ ................................ ....... 10 ABSTRACT ................................ ................................ ................................ ................................ .. 11 INTRODUCTION ................................ ................................ ................................ ........................ 12 RESEARCH BACKGROUND ................................ ................................ ................................ .... 15 Water Issue and Climate Change ................................ ................................ .............................. 15 Global warming and extreme weathers ................................ ................................ ..................... 16 LITERATURE REVIEW ................................ ................................ ................................ ............. 18 Urban Drainage and City Inun dation Problem Around World ................................ ................. 18 Policies and Law for water management locally and worldwide ................................ ............. 22 Storm water design and pollution control strategy ................................ ................................ ... 23 Storm water managem ent and storm mater measurement ................................ ........................ 25 Constructed Wetlands Used for Storm Water Treatment ................................ ......................... 26 Runoff treatment with wetlands and runoff water pollution control ................................ ........ 26 Run off water pollution control ................................ ................................ ................................ . 27 METHODOLOGY ................................ ................................ ................................ ....................... 28 Overview of methodology ................................ ................................ ................................ ........ 28 Study area selection ................................ ................................ ................................ .................. 28 GIS Model design ................................ ................................ ................................ ..................... 29 ANALYSIS ................................ ................................ ................................ ................................ ... 31 Climate statistics and rainfall frequency ................................ ................................ ................... 31 Elevation ................................ ................................ ................................ ................................ ... 34
6 Description of watershed ................................ ................................ ................................ .......... 36 Population distribution ................................ ................................ ................................ .............. 39 Land use ................................ ................................ ................................ ................................ .... 40 Possible pollution sourcend and inundation point analysis ................................ ..................... 41 DISCUSSION AND SUGGE STION ................................ ................................ ........................... 45 Storm water management in neighborho od scale ................................ ................................ ..... 45 Storm water management in watershed scale ................................ ................................ ........... 50 CONCLUSION ................................ ................................ ................................ ............................. 54 APPENDIX ................................ ................................ ................................ ................................ ... 54 LIST OF REFERENCES ................................ ................................ ................................ .............. 56 B IOGRAPHICAL SKETCH ................................ ................................ ................................ ........ 63
7 LIST OF TABLES Table page P ossible pollution source analysis Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰.Ã‰Ã‰ Ã‰Ã‰Ã‰Ã‰Ã‰ 38
8 LIST OF FIGURES Figure page Figure 1 Precipitation of W uhan from 1962 2012 Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰ Ã‰Ã‰Ã‰..31 Figure 2 Wuhan's monthly precipitation by percentage Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰ Ã‰Ã‰Ã‰. 33 Figure 3 Analysis of water inundation point Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰ Ã‰Ã‰Ã‰Ã‰Ã‰..Ã‰42
9 LIST OF OBJECTS Object P age Hubei province administrative regionÃ‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰....34 Elevation of HubeiÃ‰Ã‰Ã‰Ã‰Ã‰Ã‰ Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰.34 Wuhan Water bodyÃ‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰ Ã‰36 Shape change of north lake in Wuhan Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰.. 38 Inundation Point in Wuhan in 2011.6 and 2013.6 Statistic from Wuhan Government Ã‰Ã‰Ã‰Ã‰. 43 Suggested Area for Implement S tormwater ManagementÃ‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰ .48 Wuhan Main city park locationÃ‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰Ã‰ .. Ã‰ 52 !
10 LIST OF ABBREVIATION S BMP Best Management Practices DCW Digital Chart of the World GIS Geographic Information Systems LEED Leadership in Energy and Environmental Design LID LIUDD Low I mpact D evelopment Low I mpact D esign and D evelopment NEA NPES PUB SWM SUDS WSUD National Environment Agency National Pollutant Discharge Elimination System Public Utilities Board Storm W ater M anagement Sustainable Urban Drainage System Water S ensitive U rban D esign
11 ABSTRACT OF DISSERTATION PRES ENTED TO THE GRADUAT E SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLME NT OF THE REQUIR EMENTS FOR THE DEGRE E OF DOCTOR OF PHILO SOPHY ANALYSIS OF STORMWATER MANAGEMENT SYSTEMS IN WUHAN, CHINA By Rong Sheng August 2015 Chair : Nawari, Nawari Cochair: William L. Tilson Major: Sustainable Design With the quick pace of urbanization and dras tic transformation of economic form, Wuhan, a central city of China is faced with serious inland inundation problems in recent decades. This study intends to alleviate Wuhan's storm water management problems in sustainable way and give suggestions as to th e improvement of residential area storm water management and lakeside wetland protection. Based on the data provided by Geographical Information System, analysis is done to the land form of the whole city and the change of its lake areas, which evidently d emonstrates the influences of economic development on the natural environment of the city and reveals the causes of the inundation problems. Taking the population growth, land use and climate change into consideration, this thesis argues that strategies su ch as green roof fostering, neighbor hood water reuse and wetland conservation can make a difference in rain water drainage and prevention of inland inundation in Wuhan. Key words: inundation, green roof, watershed reservation
12 CHAPTER 1 INTRODUCTION S ustainable design helps people to live a better life with lower living cost without squandering the resources of the future generations. The gold principle of sustainable design tells us to capture, store and distribute resources reasonably to low down the consumption of energy use to the least. How to use sustainable strategies to make the city a better place to live without harming the environment ? That's a problem we all need to consider. If we can take care of water, we are well on our way to the prot ection of environment (John Randolph 2011). Urban inland inundation is a problem that faces many cities during their development time. Wuhan is a city well known of plentiful water. Abundant water comes from the hundreds of lakes and two main rivers Yangzi River and Han River, which join together here in Wuhan. The 110 kilometer shoreline of lakes gives citizens great opportunities and wonderful views. About a quarter of the city area is lakeside area. In ancient time Wuhan was an important port for water t ransportation. The 1800 years of history also gives Wuhan rich culture. In June of 2011, Wuhan was attacked by heavy storms which lasted a long time and 88 regions in the city were facing serious storm water ponding problem. The inland inundation led to tr ansportation system tie up. What's more, the polluted water led to the cutting out of electricity and shut down of the clean water supply system in some areas of the city. Tens of thousand people were influenced by the storm. Similar situation appeared in the July of 2013, when heavy rain fall lasted 40 hours and people were besieged in the train station as road system was ruined by queued cars. The direct economic loss of this disaster is up to 2 billion Yuan. A joke once spread wide on the Interne t about city Wuhan ,which says Ã” Goes to Wuhan in summer to see the sea!' The point is that Wuhan is an inland city far away from the sea, so how can this even possibly happen? Frankly, this scenery not only appeared, but also happens once or twice a year, but only during summertime. The flat form of land called Jianghan Plain gives Wuhan opportunities to expand its city area in all the possible directions but at the same time, inland inundation starts to appear. Citizens doubt if the city's sewer system really work s? Government was also confused because they have already spent money on this problem but it still can't be solved well. After several days of heavy summer rain, water will fill up lakes and other low lands in the city. When large lakes have been filled up and combined with some road area, here the Ã”sea' scenery comes
13 into view. In the city development perspective, nothing is more important than design for people's well being and convenience. Urbanization changes the natural landform in many ways. For ins tance, the original grassland and woods have been replaced by the increasing proportion of residence areas that accompany increasing density of people. With time going by, the rapid increase of hard surface of the ground and building houses directly leads to the dramatic decrease of evaporation. Many natural wet land and pond have been filled or destroyed. According to statistics from WuhanÃ”s city design department, Wuhan's lake decreased from 147 to 27 in 2009 while from 1949 to 2005 Wuhan's city construct ion land is expanded 8.5 times. About 225.42 myriad squarer meters land has been used as city developing construction land but only 0.055% land was used as city green field. In only two years of 2002 and 2003, real estate's land use was up to 693.5 myriads and 511.5 myriads squared meters(Wuhan Water Affair Bureau .gov 2015.6). Underground water didn't get enough supply; City inland flooding causes traffic jam and roadblock. With the abundant of storm water shower, financial loss and injury of people are l ike the wounds of the city. How can we alleviate the inland inundation without harming the environment and benefit citizens' life? Sustainable design can help alleviate both the water pollution and inland inundation, make use of falling water, reduce run o ff pollution and protect our city by the way of nature. Storm water management and watershed restoration is not a sole domain of construction and engineering; it is an interdisciplinary field combining many subjects such as soil science, ecology and hydro logists. Citizens, land users and planners are linked together by this art and science mimicking problem. Storm water management (SWM) attracts more and more scientist's attention because it's now not only the problem of building drainage to get water out as quickly as possible so that it will not cause flooding. Actually, the control measures have evolved from centralized structure to distribute and onsite practice and from man made structural methods to natural and biological one, that is, what is called low impact development (LID) measures(Elliott and Trowsdale, 2007), Water Sensitive Urban Design or WSUD, Sustainable Urban Drainage Systems or SUDS (UK; Elliott and Trowsdale, 2007) and Innovative Stormwater Management
14 (Marsalek and Schreier, 2009); It e mphasizes onsite development ordinance and storm water impact fees. Through the development of sustainable design and focused research on storm water management, various approaches have been found. Source control is more used than the original separate sto rm water pipes or combined sewage (Martin et al, 2007);"techniques alternatives" are more frequently used in France. This study may find the suitable strategies for Wuhan to address the inland inundation problem. To use those ways to analyze and measure la nd forms in Wuhan may help to solve the problem of inland flooding. On the other hand, runoff pollution is another aspect of the issue that needs to be addressed. In this case, the runoff water quality influences Wuhan's hundreds of lakes. The study aims t o find the ways to decrease the pollution and give suggestions about minimizing runoff pollution in different ways.
15 CHAPTER 2 RESEARCH BACKGROUND Water Issue and Climate Change Water covers 70% of our planet, so people often consider tha t there will always be plenty of water. However, drinkable water is actually incredibly rare. Many of the most profound and immediate impacts of climate change are related to water. Since 1900, more than 11 million people have died as a consequence of drou ght(United Nations Global ,2012). At the same time, in developing countries, 70 percent of the industrial waste is dumped into water, which polluted the usable water supply directly. 60% of the world's 227 biggest rivers have interrupted stream lows due to dams and other infrastructure. Interruptions in stream low dramatically decreases sediment and nutrient transport to downstream stretches, reducing water quality and impairing ecosystem health (UN WWAP 2003). Saving water and recycling water now become a world issue. This is what is meant by saying if you deal well with water you are on your way to sustainable and environment protection. The situation for water scarcity is more severe in China. With the insufficient water resources to meet rising water c onsumption, water shortage and low water quality start to threaten the living quality of people's life. According to analysis, three factors contribute to China's water scarcity: uneven spatial distribution of water resources; rapid economic development an d urbanization with a large and growing population and poor water resource management (Yong Jiang, 2009). When special asymmetry of water resource meets with inconsistency social economic demand for water, then here comes the conflict between demand and su pply. This conflict may be accelerated by economy growth, population growth and China's quick step of urbanization. The northern part of China contains 45.2% of the country's population but only has 19.1% of the country's water resource (China Resource, 20 09). The demand by agriculture, industry and households for water increases dramatically, the availability of water becoming one of the most important key factors of regional development. The low water availability in many local areas north of Yellow River in China brings life trouble to its people. In addition, Climate change also aggravates the situation. In the Yellow River basin, weather becomes drier and average temperatures have increased while river run off have
16 decreased in the past 50 years(Fe et a l, 2004; Liu and Xia, 2004, Yang et al, 2004). A general decrease in the number of rain days has also been observed trough the whole country( Shilong Piao, Philippe C 2010). In the past 20 years climate change decreases the annual flows of Yellow river by 15%(MWR, 2007 b). The statistics from 412 meteorological stations shows that a strong warming is now taking place in China during the past five decades. The temperature has increased by 1.2 since 1960. The seven warmest years all appear in the recent decade. What's more, the latest century was the warmest century since 1600 (Science Press, 2007). At the same time, increasing rain fall shows great contrast between northeastern and southern C hina. It means that Southern part of China is experiencing more rainfall during both summer and winter time. The similar region of northern part of China is receiving less precipitation in both summer and autumn. The weakening of the summer monsoon can dat e back to 1970s (Ding, Y. & Dong, W. 2005) In the bigger picture, China has already suffered from some devastating extreme climates. For instance, the big flood of 1998 inundated 21x10 6 hectares of land and destroyed five million house in the Yangtze bas in, the economic loss of this hazarders being up to over $20 billion US dollars (Shilong Piao 2010). China is at high risk of heavy rainfalls and drought. The reduction of cold winter days has also been recorded (Zhai, P. M. & Pan, X. H.2003). Floods and e xtreme events caused by High special heterogeneity and heavy rainfalls become more frequent in mid and lower reaches of Yangtze River. About 50% of the precipitation is received as heavy rain storms. Those summer storms bring high risk of summer flooding i n the Yangtze during the past 40 years (Shilong Piao, Philippe C 2010). Extreme heavy rain brings many troubles to inland city, one of the most serious being inland inundation. Global warming and extreme weathers Climate change has long since ceased to b e a scientific curiosity, and is no longer just one of many environmental and regulatory concerns. As the United Nations Secretary General has said, it is the major, overriding environmental issue of our time, and the single greatest challenge facing envir onmental regulators. It is a growing crisis with economic, health and safety, food production, security and other dimensions. Shifting weather patterns, for example, threaten
17 food production through increased unpredictability of precipitation, rising sea l evels contaminate coastal freshwater reserves and increase the risk of catastrophic flooding, and a warming atmosphere aids the pole ward spread of pests and diseases once limited to the tropics. (UNEP Climate change introduction 2010) Recent U.S. and inte rnational assessments of climate change show that global average sea level rose approximately 1.7 millimeters per year through the twentieth century after a period of little change during the previous two thousand years. Observations suggest that the rate of global sea level rise may be accelerating. In 2007, the Intergovernmental Panel on Climate Change (IPCC) projected that global sea level will likely rise between 19 and 59 centimeters (7 and 23 inches) by the end of the century (2090 to 2099), relative to the base period (1980 to 1999), excluding any rapid changes in ice flow from Greenland and Antarctica. According to the IPCC, the average rate of global sea level rise during the twenty first century is very likely to exceed the average rate over the la st four decades. (EPA Climate Change Indicators in the United States 2014) Relatively small changes in mean temperature can result in disproportionately large changes in the frequency of extreme events. According to statistic, Des Moines, in the heart of t he U.S. Corn Belt, currently experiences fewer than 20 days above 32 (89.6 ); this would double with a mean warming of 2 (3.6 ). For similar warming, Phoenix, where irrigated cotton is grown, would have 120 days above 37 (98.6 ), instead of the current 9 0 odd days (James G. Titus, U.S. EPA 2009). Sequential extremes can affect yields and diseases. Droughts, followed by intense rains, for example, can reduce soil water absorption and increase the potential for flooding, thereby creating conditions favoring fungal infestations of leaf, root and tuber crops in runoff areas.
18 CHAPTER 3 LITERATURE REVIEW Urban Drainage and City Inundation Problem Around World In the human perspective, the most valuable benefit of an effective urban drainage system is the maint enance of public health (David, John W. 2000). In tropical countries the effective drainage system can directly reduce the habitat of mosquito and decrease the possibility of disease spread. Tracing the history of urban Drainage system, several thousand ye ars ago artificial Drainage system was developed in many ancient civilizations. The Romans are famous for their public health engineering which includes the aqueducts leading water into city. What's more, the cloaca maxima built to drain the Roman Forum is still in use today. Other civilizations such as the Geeks(Athens) and Minoans (Crete) also have similar projects (David, John W. 2000). London as an example of Urban Drainage system development has a long history of water management. In the 1770 17 80 flus h toilets became popular but it still discharged to cesspits at that time. By the 1817 population of London grew up to one million. The cesspits remained a serious problem in poor areas when latter time cesspits were connected to sewers and the problem mov ed from the city to rivers. By the 1850s, the river was filthy and disgustingly stinky. In the 1854 18 59 a more serious disaster occurred, that is, the spread of Deadly Cholera. Tens of thousand Londoners were killed by this disease. Edwin Chadwick, refor mer of the Victorian sanitary finally argued for a dual system of drainage: one for human waste and one for rain water. Ã”The rain to the river and sewage to the soil' is the word of him. Until after Second World War many parts of UK started to have effecti ve wastewater treatment facilities, but there still was water pollution during the wet weather. Most of the problems come from the sewers that combine the waste water together with the storm water in the same pipe, witch is a great pollutant of river and s erious waste of water. Big changes came in the 1980s when computer modeling started to introduce sewer system design. The first pack of modeling system is written based on the amount of rainfall and pipe flow calculation called Wallingford Procedure lunch ed in 1981. During the 1990s, Urban Water Treatment Directive ( Council Directive 91/271/EEC of 21 May 1991 concerning urban
19 waste water treatment ) was established. The association contributed to the treatment of wastewater and moved it into a new level. Se a disposal was finally banned by late 1998. A specified minimum level of wastewater treatment has been created based on the city population size and type of receiving water. The whole program was finished in 2005, from that on, the water management st arted in the right direction. In other countries, situation differs from place to place. In Aorangi, Karachi, Pakistani, people have no sewers until the 1980s, the wastewater is discharged directly to local rivers wit hout treatment (New Scientist, June 1996). I n Hong Kong, China residence discharged their toilet waste into septic tanks and the problem of these tanks is that the maintenance was very difficult, plus overflowed tanks may cause problem for community function. Meanwhile the discharge of sullage pollu ted streams and rivers and costal water which led to Ã”red tides'. In Jarkada, Indonesia, high density of people requires well designed drainage system but on the contrary for a city of 127000 , no urban drainage system has been established. Most of the 700 000 m ! of waste water goes directly into dikes, canals and rivers. Some areas of the city get seasonal flooding. As response existing drains have been reclined in some locations so that the storm water is routed more directly and quickly into sea (Varis an d Somlyody, 1997).Urban drainage systems have to deal with two kinds of unwanted water: waste water and storm water. In urban drainage history wastewater was connected to ditches and natural streams whose original function being carrying storm water. (Urba n drainage system 2000) From the late 80s last century Americans started to tackle the problem of storm water pollution. In that situation the United States Environment Protection Agency (EPA) joined hands with US government to do investigation and survey through the whole country and to seek the best ways to cope with storm water management problems and city inundation problems. Based on the results of investigation, the Best Management Practice for water pollution was implemented. This pollution control s ystem refers to complementary pollution controls in many fields such as industrial wastewater control and multiple water sewage control, and especially storm water management in both urban and rural areas. Utilizing the multifunctional storage facilities, installing pipes for controlling pollution, BMP effectively solved most of the problems. But still some back sides of the strategy showed up. For instance, in some high density building areas large range of water storage facilities are not built. Another c hoice of storm water management is called Low Impact Development.
20 As a new notion of storm water management strategy, LID takes advantages of the original site situation: the water terrains and other environmental features to manage storm water through wat er garden and infiltration pavement etc. It meets goals of reducing water flow in pick time, controls pollution from the start point and manages water quality in the whole region. To back up the new water management strategy and offer technical and logisti c help for it, State government and local counties start to make laws and restrictions to achieve scientific management. Clean water restrictions, the National Pollutant Discharge Elimination System (NPDES) requires that industrial, municipal and other fac ilities must obtain permits if their discharge goes directly to surface waters. All the construction activity and industrial activity must get the certain permission for discharge. The NPDES permit program is responsible for significant improvements to Uni ted Nations water quality, in that way America start to go on the higher level of water management. More ever, nearly every year the organization will give reward to those programs that manage storm water with new innovation strategies to stimulate the pro gress of water management related innovations. In Japan, situation is much more different. By the bless of the specific location, the rain fall of whole year seems even, the average rainfall is approximately 1800 mm. Though by the influence of thunderstorm Japan's one time falling also can reach up to 400 mm. During the high speed of urbanization Japan also suffers from city inland inundation problem, to cope with the storm water, they built large amount of storm water management storage facility, the probl em is the hardened reservoirs have low usage rate and high cost now it has been replaced by newly multifunctional storage reservoir. Those new multifunctional storage reservoirs become one of the most important ways for Japanese to cope with the inland inu ndation. In the mean time, Japan makes use of nearly all the public recreation land and open squire space for storm water management. Those places were designed with function of water storage during storm time, which contributes to the improvement of the s torm water management ability in the whole region. Japan started the second city plan action in 1992, during this process the rainwater infiltrate, storm water management have been included in the whole city plan. It requires all the new building and rec onstruction projects to consider the falling water treatment. The related restriction of out discharge is very strict. Situation in Germany is quit different because of the plentiful rainfall. The inundation problems bother many big cities in Germany. Faci ng the challenge, Government started to
21 handle the rainwater in two directions, one is to evacuate, the other is to use. The management and control start with these two parts. On the one hand, they improve the infrastructure of water management system, bui lding falling water management facilities and reservoirs to control the evacuation time and flow and reduce the pick time water amount. On the other hand they invest money in water recycling and gray water reuse, technically supporting the transformation f rom simple storage to ecological ways to infiltrate rainwater. Facilities have been prepared to transfer to more centralized and automatic function than before. China now is faced with serious problem of city inland inundation. It is a hard problem to sol ve because it is associated with many different departments of Government whose cooperation is crucial in the solution of the problem. Some of the researchers already start their steps in solving these problems in big cities such as Beijing and Guangzhou. Because of the high speed of China's urbanization city harden surface grows fast. At the same time, climate change leads to high frequency of extreme weather. What's more, the city drainage system itself still got many problems which directly lead to the p onding and inundation problem. According to the investigation done by Ministry of Housing and Urban Rural Construction of the People's Republic of China in 2010, from 2008 to 2010, 351 cities have taken part in the statistic analysis of inland inundation, 62% of all cities faced with the inland flooding problem. To meet the challenge of city inland inundation there is no time for waiting, because the problem not only causes economic loss but also threatens city security. But situation in china is quite comp licated, for the land inundation problem is related to many different management departments and different branches of subjects. To tackle this challenge, China still lacks long term plan and statistic and scientific foundations. Some of the solutions now offered can only cope with instant problems. Some of the researches only focus on how to evacuate the inland pounding water as quick as possible, but researches about evacuation and drainage system standard have certain limitations as they are usually base d on certain small sites and areas. The inland city inundation is complicated by two factors. The first one is the natural trigger and the second is human interference. In the human part. the reasons can be listed below according to studies of researchers. First of all, the specialized standards to cope with the urban flooding in some regions are out of date. Secondly, the legislation of government is not complete for water management and pollution control. The city planning system is not complete especiall y on urban water drainage part. In some city the history problem in drainage systems also enhance
22 the challenge. Thirdly, the technique support of urban infrastructure can't fit the demand of quick growth of city area. New technology support is not put int o practice sufficiently. Last but not least, facility maintenance after the construction is still a big problem. Associated department for maintenance still lack professionals. Those factors now trouble the development of improvement of China's Water manag ement innovation step in every happened moment now. Policies and Law for water management locally and worldwide One important aspect of water management and protection is the restrictions and laws for water. To see how country manages the water, the mo st efficient way is through their water laws, because it deals with the ownership, control, and management of water resources directly. The growing population and highly competitive market make the natural resources become precious. More and more governors and professionals are working on the probable balance between the conflict of the growing demand for water and limited resources. Laws as an important way to protect water resource from pollution should contain wide range of factors with a long term aim. Climate change, changing pattern of rainfall and cost of sewage clean system should all be considered. With the development of country and region revising law from time to time is also important. In The United States, multiple legal systems are now involve d in water management control and protection. Water law covers wild range of subjects such as public health and water protection. As for the range for water laws some of them are derived from states, some are for certain region and others are local regulat ions. Situations are similar in China. One important law was published in 2008. With the publish of this law China's step to the environment protection goes further on the way to water protection. This law is a general restriction to both china's water us age and discharger in industry and agriculture. It has deep influence on China's Environment protection, because it clears the responsibility and obligation from large corporations to small companies. The original Water Pollution Prevention and Control Law was adopted in the fifth session of the Standing committee of the six National Peoples congress on May 11th, 1984, it was revised in May 15th, 1996. With the development of the county, serious environment problems and horrible consequences led by the brok en natural chains and severely damaged environment require immediate rectification measures. To face the situation, Chinese government revised the law again and this law came
23 into force in 2008. In the development of China's water management history, seve ral things need to be mentioned as great steps for china's development. From the beginning of the 20th century the pollution problem shows sever consequences in China, for instance from 1985 1989 in only one province, 10126 people were killed because of th e pesticide pollution. It is 10 times to the traffic accident death at that year in that province. Protect the drinking water is a problem needing immediate attention. The main source of water pollution includes industrial waste water, pesticide from the o ut field and fertilizers and domestic swage. By the year of 1998 the domestic swage pollution exceeded industrial waste water. To face the challenge, Chinese government took several actions to cope with the situation, including revising the Water Pollution Prevention law. The idea of Water Pollution Prevention and Control Law is to safeguard the drinking water safety and enhance the comprehensive and harmonious development of Chinese society. The law focused the prevention and control of water pollution. Th is law required both the supervision and administration of the prevention and control of water pollution in different state departments. It requires the local government to take action to the pollutant source with no exceptions. All the factors should be taken into consideration when planning drainage system. This law also makes certain action requirements for how to prevent pollutants and how to deal with pollution. For instance, in the chapter for the prevention of Urban Water pollution, concentrated tre atment of water pollution, overall planning and arrangement for the construction of facilities are all required by law. As for entities, they must pay for the provided services which include sewage treatment. Discharging pollutants must be in accordance wi th state provisions. The pollution control facility maintenance after the construction used to be a problem associated with department responsible for maintenance, which usually lacks professionals, now the law requires that all the Sewage treatment fees c ollected shall be used for the construction and operation of sewage concentrated treatment facilities only ( Water Pollution Prevention and Control Law). Now China's government are still working on the restrictions and monitoring of pollution prevention sy stem. Storm water design and pollution control strategy Many efforts have been made in storm water design, alternative approaches including infiltration of falling water in site, rainwater management and pipe design , detention of rain fall on site to sta gger the peak time of storm drain off during the large storm event. Run off design is
24 a crucial part of storm water management which should not be neglected. Innovative storm water management and design must be based on the rainwater amount and frequency o n the site. The correct way is to consider storm water design from the level of neighborhood, and magnify it to watershed and region, then scale up to city plan level step by step after considering the collection, storage and reuse process to prevent the r ain off water pollution from the source. Storm water design from the neighborhood scale has a lot of choices to consider too. City high density residential area should have different design strategies from large and less concentrated areas. With the simila rities of both parts, the same solutions could also be used. For instance, the public garage or parking lots could be a very good choice to start with. Traditional open space parking lots have hardened surface instead of water permeable bricks. This result s in the less infiltration area for rain water. Rain water run off traditionally goes into sewer system of urban storm water pipes that conveyed into drainage system and streams. Traditional residential houses roof run off often goes directly into sewage s ystem. With the development of green roof the situation will be much more different. What's so special about the Green Roofs is that they have multiple functions. Green roof can catch some of the falling water and reuse it for itself. The extension green r oof provide gutters for storm water collection and then the infiltration bio swales retain the water for underground water supply and rain garden water supply. In the watershed scale, lakes and ponds are the important places for water management and reclai m. In China, some city's storm water goes to the nearby lakes and streams directly, the discharge water may be polluted by untreated storm water for the garbage and pollutants on pedestrian easily go with storm water. Once it has been discharged into the l akes, all the life entities will be influenced by the discharged water. Wetlands as the most important part of water discharge and storage area in the city should be considered and be protected in city range. Effective pollutant control strategies are desc ried in many researches. For instance Street Sweeping as a Method of Source Control for Urban Storm Water Pollution, written by Rochfort et al in 2009. The maintenance of Urban watershed and sediment considered operations are suggested in the paper Sedime nts Assessment of Storm water Retention Ponds within the Urban Environment of Calgary, Canada.(2009) by Westerbeek vopicka. As for City planning scale, a lot of things still need to be considered during the planning process. First, probable drainage syste m should be taken into consideration. China's many big cities don't have probable scale of draining system. For instance, Wuhan's sewage system is one
25 of the main reasons for the serious inland inundation. The volume of storm discharge limits the drainage speed of peek time water. The occurrence interval of Wuhan is P=0.33 to 0.5 years , the basic requirement of modern city storm water management is P=2 to years, suggested by Liu weiguo in Wuhan Urban and Rural Construction Commission. Creating large scale water management system and wetland conservation to improve the microclimate of the whole could be possible way to protect our environment and improve the water quality in local lakes. Storm water management and storm mater measure ment Strategies for sus tainable storm water management are needed at different decision levels, but all of them need information and a clear understanding of the original site. A sound approach to storm water management should be flexible, based on local characteristics, and sho uld take into consideration temporal, spatial, administrative factors and laws among other issues. Best Management Practices should be seen as an opportunity for development and improvement of social, educational and environmental conditions in urbanized and surrounding areas. Therefore they require an ample perspective and the participation of different stakeholders. High quality decision needs time and a fair overview of the problem: the purpose of this document is to contribute to sustainable storm wate r management, informing on the most relevant factors that should be assessed and their interaction. A flowchart has been produced and is presented, indicating the most relevant steps, processes and information that should be taken into account in urban dev elopment (Key issues for sustainable urban storm water management. E. Barbosa, J.N. Fernandes, L.M. David). In the last years, the attention on integrated analysis of sewer networks, wastewater treatment plants and receiving waters has been growing. Howev er, the common lack of data in the urban water quality field and the incomplete knowledge regarding the interpretation of the main phenomena taking part in integrated urban water systems draw attention to the necessity of evaluating the reliability of mode l results. Uncertainty analysis can provide useful hints and information regarding the best model approach to be used by assessing its degrees of significance and reliability. Few studies deal with uncertainty assessment in the integrated urban drainage fi eld. The Generalized Likelihood Uncertainty Evaluation (GLUE) methodology, which is widely applied in the field of hydrology, can be a possible candidate for providing a solution to
26 the above problem. However, the methodology relies on several user defined hypotheses in the selection of a specific formulation of the likely measurement. Constructed Wetlands Used for Storm Water Treatment Storm water management in urban areas is becoming increasingly oriented to the use of low impact development (LID), susta inable urban drainage systems (SUDS), water sensitive urban design (WSUD), best management practices (BMP), or low impact urban design and development (LIUDD) for countering the effects of urban growth, wherein the storm water is controlled at its source t hrough detention, retention, infiltration, storage, and retardation (Charles worth et al. 2003; Elliott and Trousdale 2007; Kirby 2005; Martin et al. 2007). These methods include structural measures such as wetlands, ponds, swales, soak ways, infiltration trenches, roof storage systems, detention/retention basins, infiltration basins, bio retention devices, vegetated filter strips, filter strips, and pervious pavements. Though the management ways are varies from place to place and varies by climate and geog raphic matters but u nder appropriate conditions, these structural measures have proven to be effective (Goonetillekea et al. 2005). Runoff t reatment with w etlands and r unoff water pollution control The use of constructed wetlands for the treatment of dome stic wastewater is now well established in the UK. Their ability to treat a range of industrial wastewaters is now being investigated. The ability to treat urban runoff in UK are now relatively untested despite the fact that this application could have imp ortant environmental and operational benefits, in both industrial and developing countries. Environment Agency have developed constructed wetland treatment systems at two selected sites in south east England, both of them receive large volumes of urban run off every year . The sites are located at Brentwood and Dagenham and were completed in April 1995. Water and sediment samples have been collected at bi monthly intervals at each site since October 1995 and analyzed for a range of parameters including the to tal concentrations of six trace metals Ã‘ cadmium, copper, nickel, chromium, lead and zinc. Similar analysis has been carried out on plants collected from both sites in the spring of 1997. The largest pollution often come from the " F irst Flush", the first 6 8mm of storm volume may include 60% percent or more pollutant loads from industrial parks in Taiwan (Chang et al 2008).
27 Generally speaking storm water management can be divided into two parts, control from the source, and manage by sewers. Run off water pollution control The development of buildings, roads and other surfaces using impermeable materials results in the loss of natural water retention provided by soils and vegetation (Merritt, 1994). Such urbanization alters the natural hydrological cycle, changing peak flow characteristics and the volume and quality of the runoff. In UK, development sites have been engineered so that surface water is directly drained to the closest watercourse as quickly as possible to prevent flooding. Many city in the wor ld now still use this way to evacuate water. However, this system ignores the potential pollutant loads generated from urban runoff and their impacts on receiving waters (Mungur et al., 1995), hence this form of pollution dilution treatment is now being di scouraged. The pollutant load of urban drainage waters tends to be highly variable even within a single catchment area. Concern about the quality and management of urban runoff increased in the 1970s following several studies in the USA which showed that h igher pollutant levels are associated with more intensive development and that urban runoff pollutant levels may be comparable to secondary treated wastewater effluent (Livingston, 1989). The quantity of pollutants depends on a variety of factors, such as land use, characteristics of the drainage system and catchment area, the nature and frequency of storms and the weather conditions between storms (Merritt, 1994). S uspended solids, heavy metals, hydrocarbons, deicing salts, faucal coliforms and particulate pollution originating from road and vehicle wear are all sources of pollutant . According to study, a ll urban surface runoff generates a pollutant load, although highways may occupy only 5 Ã 8% of a catchment area, they can contribute 50% of suspended solids , 16% of hydrocarbons and 35 Ã 75% of heavy metals (Ellis and Revitt, 1991).
28 CHAPTER 4 METHODOLOGY Overview of methodology This study analyzes the geological conditions and special changes to watershed in Wuhan China. Taking the city's rainfall frequency and climate characteristic into consideration in the preparation for large amount of water falling in a short time, this study will seek the best green field use for rainwater drainage, estimate the ruff improvises surfaces and seek the possibility of red ucing the infiltration surfaces. The development of economy and unprecedented pace of urbanization bring enormous changes to the surface and land use in the city, to find possible pollutant sources and fine possible ways to prevent pollution is anther goal for the research. Arc GIS is used to provide land use information to classify the land cover types in different periods of time of history; A data set is used to create raster to see the changes that appear in the area, especially the change of water body shape during the examined period of time. In order to determine the accuracy of the image classification, we specify certain points as sample points to achieve overall accuracy for statistic and add base map for detailed analysis. Land use table is create d to describe the land cover type within the studied area. The soil and conservation services area layer is planned for the best suggested storm water management area for storm Water Park and storm water recycle and management area. This study will also id entify the proper plants that are suitable for ecological water cycle system and rain gardens. Green roof area for drainage and water reuse neighbor hood is chosen. On the basis of extensive review of literature and documents for storm water management str ategy, suggestions are given to cope with inland flooding in different land scales in Wuhan. What's more, one specific case study of another city is done to make comparison with watershed management project in Wuhan in order to gain deeper understanding of the research problems. Study area selection Local storm water management problems are mostly solved individually rather than by water range. First, we outlined the watershed boundary on topographic and drainage map of the whole Wuhan district and divide d the three analysis watersheds into separate shape files. Then,
29 we drew the links and the flow pattern of canals linking to sites and down stream areas. This paper will focus on the watersheds located in Hongshan and jiangxia district in the northeast sid e of Wuhan. Measurement of independent variables was conducted using Geographic Information Systems (GIS) technology and aerial photography and watershed models were made for basic analysis. The Wuhan local government identifies 166 different watersheds in the City of Wuhan. This study will just include part of the lakes and water bodies. An important step is to identify the water boundary of lakesides such as Donghu Lake, Yanxi Lake, Nanhu Lake,Tangsun Lake, Huangjia Lake, shahu Lake, in the land shape fi les and digitalized topographical maps with the right scale. The data are from various sources while the analytical data are based on the original geological sphere of Wuhan. Though the land shape may change from time to time and the watersheds are formed through the city development, the impact of environment can't be denied. The significant impacts of urbanization on city microclimate and water quality are revealed by the statistic record and former researches. The study areas are not randomly selected. T he whole region belongs to Yangzi river basin. The Jianghan Plain hosts hundreds of lakes together in this region. At the same time the distribution of water is quite uneven in Hubei providence, for in the southern region the deepest water flow can reach 1 200 to 1400 mm whereas in the northern region, the depth of water flow may be less then 200mm. The difference between north and south is quite 6 to 7 times to each other. Wuhan, as the capital city of Hubei providence as shown on the map, is located in the southeast of the province, enjoying the most abundant watersheds. According to the statistics offered by Yangzi River Reconnaissance and Design Research Institute, though Wuhan has such an amount of water, still it can't satisfy the estimated water demand of its people, the deficit of water supply is 0.197 to 0.478hm2/person. GIS Model design The use of the Geographic Information system(GIS) technology makes local environment analysis more scientific and manageable. The system can help to visualize , anal yze and interpret data to let people know more about their study area and do the best estimations concerning land surface for the certain region. In this study, the regional layer of Wuhan and Hubei province will be used for proper analysis both specially and graphically. Measurement chart of areas and regions will be created for analysis. The data source varies and through the edit and measure test some of the data is reformed to be more accurate. One of the basic sources of the data is Harvard
30 University GIS Information Center which is reedited by Arc GIS Desktop10.3. Other data are from the Global Administrative Areas (GADM) data base, which is a special database of the world administrative areas for use in GIS, and The Digital Chart of the World (DCW), w hich is a comprehensive GIS global database freely available as for 2006. The shape file of watershed for China is from the Harvard University China historical GIS database. Road system and population shape file are also from Harvard University China data center. " Rivers of China" are from National fundamental GIS of China. The elevation data of Wuhan are from CGIAR CSI GeoPortal . Thanks go to all the organizations which provide the data for researchers to do the analysis, for their effort s for statistic c ollection contribute greatly to the progress of this field. This study will manage the data which contains the whole area of china and divide it to specific range. For instance, the watershed which covers the whole country will be clipped to provinces an d cities. Raster for watershed file will be created based on the distance from the specific lake; As for road system, the calculation will be estimated for impervious surfaces for further study and specific elevation data will be found for analysis for Hub ei and Wuhan regional analysis. Elevation portrait would let the high points and low points stand out and more understandable. Specific frequently flooded points will be selected for special analysis with Google map image and land use analysis. Suggestion will be given according to data analysis.
31 CHAPTER 5 ANALYSIS Climate statistics and rainfall frequency Located in a subtropical monsoon zone, Wuhan s temperature and climate change distinctively over the four seasons every year. The average temperatu re in the winter month is only 3 while for the hottest summer month it is 29 . The average annual rainfall i s 1150 1450 mm, which is unevenly distributed among 4 seasons with the summer season receiving 65% of the total rainfall of the year (Wuhan Climate ). Early summer every year, with the influence of Jianghuai Quasi stationary front, Wuhan experiences a plum rain season, a period of continual and intense rainfalls which usually mean flooding of rivers and lakes and water logging caused by inefficient dr ainage system in cities. After the rainy season come the summer and autumn droughts caused by Pacific subtropical high ridge. Generally speaking, thanks to the long rainy season and abundant rainfalls Wuhan is rich in water resources, which forms a favorab le condition for the economic development and people's life in the city, but the problems caused by concentrated rainfalls in rainy seasons should never be neglected. Precipitation of Wuhan is unevenly distributed over seasons every year and forms a regul ar pattern which can be clearly demonstrated with historical records. For example, the annual precipitation distribution statistics from 1962 to 2012 reveals that on average the rainfalls of March to September accounts for 72% of the year's total while for other months of the year, from September to February next year, the proportion is only 28%. Additionally, the rainfalls of PICTURE 1 Precipitation of Wuhan from 1962 2012
32 the flood season from May to September may be up to 62% of the year's total and the plum rain season from early June to the middle o f July can be washed by 24.4% of the whole year's precipitation. Except for December, which can have a low monthly precipitation under 50 mm, the other months are all favored with a figure over 50 mm and the three rainy months (May, June and July) may boas t a high monthly precipitation over 580 mm, accounting for 46% of the whole year' rainfalls. Statistics also shows that on average Wuhan experiences 4.51 days of rainstorms with a precipitation over 50 100 mm on a single day and 0.88 day of downpour with a daily precipitation over 100 mm every year. With a latitude of 30Â¡north, Wuhan is situated in the middle reaches of Yangtze River and under the influence of Jianghuai quasi stationary front, which works together with the large amount of steam produced b y numerous lakes and rivers to produce rainstorms in rainy seasons. Wuhan's storms in the rainy season feature small area, strong intensity, short span and sudden attach, which meet all the conditions for the happening of inner city water logging and flood ing. Evidence shows that Wuhan's inner city water logging and flooding are closely related to the yearly precipitation pattern. In the past 50 years, Wuhan's highest daily precipitation vibrates among the years in a relatively fixed pattern. The change pat tern is evident as the extreme figures of daily precipitation appear periodically. The years that experience the extreme figures include 1969(261.7mm), 1982(298.5mm), 1991(209.8mm), 1998(285.7mm) and 2011(194.4mm).Correspondingly, Wuhan was attached by wat er logging and flooding in years of 1969, 1980, 1983, 1987, 1991, 1996, 1998, 1999, 2011, which may be the direct result of extreme daily precipitation. The total annual precipitation of Wuhan vibrates slightly in the last 50 years. From 1962 to 1979, the annual rainfall decreased gradually and reached the bottom in 1979. After 1980 it rose steadily and climbed to the average number of the observed years in 1993, after which it vibrated slightly. From 1993 to 2004 it went up slowly and after that it reverse d the trend and fell modestly from 2004 to 2012. In the observed years, only 1979 saw a dramatic change, which happen rarely in the history.
33 As is shown by historical records, Wuhan's intense rainfall months fall on five months (April, May, June, Ju ly and August), whose rainfalls account for 66% of the whole year and the rest 7 months Ã”s average monthly precipitation is below 10% of the year's total. The winter months of November, December and January receive an average monthly rainfall under 5% of t he year's tall, relatively dry and in want of water. As far as disaster prevention and water logging treatment is concerned, the summer months should be emphasized as the climate of that period seems most suitable for the formation of storms and heavy rain s which can directly result in rainwater drainage difficulties and cause flooding of roads and communities and traffic problems. So a thorough analysis and assessment to the city's drainage ability in that period of time is of great significance to the con struction of infrastructure and city landscape and architecture planning. PICTURE 2 Wuhan's Monthly Precipitation by percentage
34 Elevation PICTURE 3 Hubei Province Administrative Region PICTURE 4 Elevation of Hubei
35 Wuhan is situated in the east of Jianghan Plain and is the transitional region from the foot hills in the south of Dabie Mountain Range to the hilly terrain in the south east of Hubei. Its geological structure is mainly Neocathasian structural system with an elevation between 19.2m and 873.7m. The north and the south of the city feature hilly terr ains while the middle of the city is low and relatively flat surrounded by long ridges, which is a typical monadnock alluvial plain. The landscape is mainly plain interspersed with hills along the east west line. Two rows of hills, one being Meizi Hill, T urtle Hill, Snake Hill, Hongshan Hill, Luojia Hill and Yujia Hill and the other including their extensions like Mafang Hill, Guizi Hill, Fuhu Hill and Phonix Hill intersect with Yangze River flowing wouth west to north east to form two axis of the city's f ramework. So Wuhan's landforms feature the interweaving of plains, hills and lakes. The proportion of plains, long ridges, hills and hilly plains to the total area of the city is 39.25%, 42.56%, 12.32% and 5,850% respectively.
36 Description of wa tershed PICTURE 5 Wuhan Water body Wuhan is a city featured of plain scattered with rivers and lakes. The major rivers include Yangtze River, Han River, Dongjin River, Tongshun River and lakes of different sizes count up to 166, among which the major ones are East Lake, Liangzi Lake, Tangsun Lake and Yanxi Lake. Within the territory of Wuhan rivers with the flowing length of 5 km total up to 165. The water coverage area of the whole city is 2217.6 km 2 , , 26.10% of the total ar ea of the city, winning for the city the title of city of rivers and city of hundreds of lakes. Yangtze River, Hanjiang River and their tributaries connect with numerous lakes to form a huge water system. Yangtze River covers a distance of 150 km within Wu han. Entering Wuhan in Hannan District, the river flows south west to north east and turns its direction to South east at Tianxin Island. The Wuhan section of Yangtze River contains large amount of water, long period of flooding and remarkable
37 change of wa ter level. The East Lake is the largest inner city lake with a coast of 110 km, and water area of 3.3xl05km 2 . , resulting in an unusual water holding capacity. Wuhan boasts of large numbers of lakes, topping all the cities of China, which is unusual in the world. The lakes are surrounded by hills or drain large areas of plain. All the lakes are shallow, flat bottomed, rich in aquatic lives, contains fresh water and demonstrate evident lake functions. East Lake East lake is situated in the east suburb of Wu chang, hence the name. As the largest inner city lake, its area is 4 times that of West Lake of Hangzhou. Shaped like letter U, the water area of East Lake penetrates several universities of Wuhan. To the south of the lake lie several low hills like Luojia Hill, Nanyu Hill, Yujia Hill and Mo Hill while to the north lie a wide alluvial plain bordering Yangtze River. With the development of the city, the area of the lake is decreasing all the time. The special geological constructions help to form the spectac ular landscape of East Lake with a folded belt zone in the east west direction. The movement of earth crust created more than 120 bays and winding banks of the lake which stretch 111 km. The lake is surrounded by complicated terrain in 4 directions with ro lling ridges to the east and west, wide alluvial plain to the north west a nd about 34 hills to the south. Shahu Lake Shalu Lake is located in the north east of Wuchang, connected with Zhongbei Road in the east, Little Turtle Hill in the south, Wuchang Da ye Railway in the south and Xudong Road in the north. A hundred years ago, Shahu Lake was connected with East Lake in the east and Yangtze River in the west, however, the three were separated after the construction of the Wuchang Qingshan embankment. At th e end of Qing Dynasty Beijing Guangzhou Railway was built to go through Shahu Lake and divide it into two parts: Inner Shahu Lake and Outer Shahu Lake. The Inner Shahu Lake was smaller and was eaten up by expanding of the land area while the Outer Shahu La ke, the bigger one remains still to the east of the railway and is the only lake in the downtown area of Wuhan. The inner Shahu lake shrink from 28.25 square hector meter in 1989 to only 6.05 square hector meter in 2009. The outer Shahu lake face even more serious lake fill, from 1989 to 2009 265.8 square hector meter lake area were occupied for other use.
38 Nanhu Lake PICTURE 6 Shape Change of North Lake in Wuhan Nanhu Lake is located in the south of Wuchang linked to Shizi H ill in the south, farming villages in the north and east. As a central lake of Wuchang, Nanhu Lake has very favorable geographical environment and natural system. With an area of 49.2 square meter a nd an average depth of 2 m eter , it is the second largest l ake of Wuhan. With the expansion of the city, Nanhu Lake now has been included into the downtown area. As it links several universities, it has been transferred from agricultural area into a commercial and residential area. With the shift of its functions, its role in city management and development has been improved to a high level parallel to a core area of the city. However, this privilege has not brought to it special treatment in environmental protection. On the contrary, it has been most severely inte rvened by human development activities. Now this lake has been encircled by large number of high rise buildings in three directions and its former boundaries have been altered by chemical factories and other
39 engineering and lost its natural beauty. Agricul ture, transportation and construction combined to cause the swift change and damage of Nanhu Lake. The change of Nanhu Lake from an area of clean water, fertile soil, rich natural resources to an over exploited commercial and living center has brought grea t threats to its landscape beauty, recreational function and fascinating visual effects. In 1989 Nuhu lake have 1527.92 square hector met er , it has decrease to 1481.26 square hector meter in 2000 and nine years latter in 2009 the lake shrinks to 937.1 squa re hector meter . During the step of lake fill and land use change 590.82 square hector meter lake area disappeared and changing to buildings and harden surface. Population distribution The city of Wuhan includes 13 administrative districts, among which 7 were inner districts including Jianghan District, the most prosperous commercial center, Hangyang, the bustling industrial zone, and Hongshan district, the region for education and 6 were outer districts of agriculture, plantation and breeding. The perm anent residents of the city is over 10 million, among whom over 650 live in the crowded downtown area of the city. Farming population constitutes 33.1% of the total and non farming population over 66%. Wuhan's population density is 984 people per km2, with Jianghan District topping all the 13 districts in this aspect and Jiangxia, a district with a fame for farming and breeding as the most sparsely populate area of the city. Wuhan is the political, economic and cultural center of Hubei Province. It has a f ame for it complete industrial system majoring in steal and iron production, optoelectronics, chemical engineering, metallurgy, pharmacy, as well as well developed and diverse traffic and transportation network plus telecommunication system. Its favorable geographical locations and advanced traffic and transportation facilities bring the city a sharp edge in economic and social development. In order to further speed up the growth of the city, Wuhan has set up the new goal of "a central city of the nation" a nd " a worldly city " and is marching to the realization of this goal.
40 Land use Lakes and agriculture land In Wuhan, lakes are filled up and turned into agriculture land. For example, between 1989 and 2000, the transformation of lakes into arable land mainly happened in Wuchang and Hanyang. Shahu Lake of Wuchang was the most severely attacked, for it has a water region with the total area of 16.62 h south of Xudong Road and north of Outer Shahu Lake bordering the railway transformed into cultivated field. Another example is the coastal area of Nanhu Lake, in which the lake plot from Xiongchu Revenue to Guanshan Road has been turned into paddy fiel ds. As the center of the city expands to Hanyang, that part of Wuhan has become a developmental area which suffers large scale of creating fields from lakes. This results in the decrease of Moshui Lake, Longyang Lake and Taizi Lake, among which Taizi Lake decreased by 157.61 h . The decrease trend spread to the lakes in Hankou too, where Zhuye Lake and Zhangbi Lake decreased by 21.61 h and 6.95 h respectively. Up to now the trend of filling lakes to create fields still continues, which results in the steady decrease of lake a rea. This reflects the government's notion of increasing agriculture input by enlarging land area, which is considered less desirable than improving agriculture efficiency by experts. A natural result of lake decrease is the rise of lake water level and th e lowering of their storing capacity. Still another effect is the damage of the natural beauty of lake banks formed in history by the newly built hard material artificial banks. Lakes and construction land In Wuhan, most of the transformed lake areas are u sed for constructing buildings of all types and the filling of lakes to create construction land happens at a high speed. The change of Wuhan's outlook shows that city construction of Wuhan started from the banks of Yangtze River and spread to other direct ions. In this process, lakes are sacrificed for the construction of buildings for different purposes. With the development of the city, lakes are filled continually and transformed into construction lands. From 1989 to 2000, Hanyang's major lakes like Moon Lake, Lotus Lake, Longyang Lake and Taizi Lake were all partly filled to create place for construction, among which Taizi Lake is filled by the largest area., a total of 27.54 h converted into construction land. Hankou hosts the smallest area of lakes am ong the three towns of Wuhan. However, as the most highly developed region of the city, its lakes have not escaped
41 the fate of being filled up and large areas of lakes were transformed into constructed commercial areas. Likewise, Wuchang's lakes were also devoured by construction sites and the loss is estimated to be no less than 170.99 h . Since 2000 thanks to the control of the government, the situation has changed for the better and the pace of lake filling for construction slowed down but it has never stopped completely. With the soaring of house price, the water region of Wuhan is alw ays the target of the house developers and land speculators. Lakes and traffic land With the improvement of Wuhan's traffic system, roads and bridges were constructed and widened to increase the fluidity of the city. One consequence of this progress is th e filling of lakes to realize the extension of roads and expansion of traffic system. From 1989 to 2000, the Houyang Lake of Hankou was occupied by the newly widened Qingnian Road by an area of 0.58 h and two new roads crossing Zhangbi Lake covers an area of 1.22 h of that lake. In Hanyang, the planned city loop road goes through Taizi Lake and covers an area of 6.57 h The same thing happened to Wuchang. The construction of the Second Bridge over Ya ngtze occupied the lake area of Simei Lake. Of the three towns of Wuhan, Wuchang suffers the greatest loss of lake area to traffic land use, which totals an area of 115.66 h , 55 times that of Hankou and 6 times that of Hanyang. Possible pollution source and Inundation point analysis Ground water flooding brings problem of pollutant in different ways, particularly during the raining seasons. The pollutants follow city hydrological cycles by way of going through pathways and highway surface, road gullies. Possibility of rainwater pollution is high but the results are severe. One of the most important influences is to worsen the water quality of nearest lakes and ponds. As all know, water bodies as an important chain of life cycle are linked with each other. Those pollutants may directly influence the drinking water source of city people and wild life. According to the analysis of both rode system and land use the pollutant source can be divided in to different parts. To reduce harms, finding out the possibl e source is considered to be the first step of moving forward. First of all, for the ground storm water movement, soil erosion
42 could be one water pollution cause, others including oil and organic matter. Secondly, for improper act of people may also lead to upper ground pollution. For instance litters and debris may happen. Massive area of construction may aggravate the situation of this problem which needs to be awear of. As a matter of fact, lack of restrictions on construction area falling water treatme nt makes soil erosion and water pollution highly possible. Thirdly, atmospheric deposition also may influence water quality. The most sever situation may appear as acid rain which directly influences the open space water quality and surface of architecture is untreated and runs off randomly. The following chart shows the possible pollutant sources. ! Pollutant Description Pollutant source !"##$%&'($)*+,! Oil , Litter , Organics, Metals, Nutrients Motorways and major road !"#$%&'()(*'&'+',(! !"#$%&'()*% !"#$%& ! !"#$%&'%()*+,(-!+%) ! !"#$%&'#()*%'$+),-&-+ ! !"#$"%&'#$()$&*%+&",()-&&&&& ! !"#$%#"&'%"(%)*'%!+)',% ! !"#$%&'()$%*+,%''-##,'./)+& ! !"#$%&'%()*%(+,''!-!.!)/(,0( !"#$%&'($)&*'!#$+& ! !"#$%"&'$()*+(,"-"&'* ! !"#"$%&'()$*+'%%"& ! !"#$%&%'()*#+&%!(,#-(./ ! !" !"#$%'(!)*$+* ! !"#$%&'()%*+," ! !"#$%&'()*+,-(&$%*", ! !"#$%&'"(#)*&+"#,*&-../"0&*& !"#$%&'$( ! !"#$%&'()*+#(%,-)'./ ! ! !"#"$%&'()$*+'%%"& ! !"#$%&'()**'+(,&"'(-*'.(*)( !"#$!%& ! !"#$%&'()$**+"(,+'$! !"#$"%&'(')'%*+&,'$*#-#.' ! !"#$%&'()*+)#($'$,)#** !
43 PICTURE 8 Inundation Point in Wuhan in 201 1.6 and 2013.6 Statistic from Wuhan Government According to the statistics by official departments in 2011, 88 high level inundation points have been spotted. The storm on June 18th 201 1 took only one day to make the inundation PICTURE 7 Analysis of Water inundation point
44 problem attract attention from all of China, from that on water department and specialists started to specify causes for the inundation problem. The two graphs show different inundation points in 2011 and 2013. Th rough the calculation four main reasons that cause the inundation problem have been analyzed. First, because of the city development, large construction area lowers Wuhan's normal ability of draining rain water. What's more, open construction area brings p ollutant into the run off water which causes serious soil erosion and lake pollution. One of the most urgent problems is that the capacity of pumping system can not face the challenge of sudden heavy rain Wuhan experiences in summer so 42 percent of the in undation was caused by inadequate pumping system. The improvement of basic capacity of pumping system now is urgent. Wuhan has only 38 original pumping stations in 2011. According to the government plan 25 drain off pumping system will be improved and 9 ne w ones will be constructed. Those improvement will enlarge the capacity of drainage system. Improvement will be implemented on the sewer system too, for 34 percent of the inundation problems is caused by imperfect sewer system. Regular maintenance will als o help release the inundation pressure. The decrease of inundation points shows the power of facility improvement, but in July 5th 2013 the the second time storm influenced more then 50 roads in the city, about 75 residence districts were affected by the rain. Inundation problem is still severe. The location of inundation points have great influence on how to drain water away and how much it will influence people's daily life. Residence area inundation may directly influence people's security and property safety so it has its own priority during analysis. Additionally, green field also may help the water drainage. For instance, many public city parks in Wuhan do not have the function for storm water management, sometimes simple change of geographic appeara nce of the open field in the park may bring out natural water drainage place to release the inundation near around park site. Residence area sustainable water management cycle linked with public city parks could create great cycle for both water conservati on and inundation release. Now all the attention and improvement for the inundation is focused on how to drain off the water as quickly as possible, is it the best way to manage water? The strategies surely help decrease the inundation point number but bet ter way of managing water is to recycle water and reuse it and link nature with people.
45 CHAPTER 6 DISCUSSION AND SUGGE STION Storm water management in neighborhood scale As basic living space for people, residential areas are considered to be the mos t important space for city life and improving the living standard of regular residential area means a lot to the city and its people. Newly developed apartments are considered as the easiest part to start with, because they embrace more advanced technology in the process of construction. Taking basic living unit into consideration and repeating the treatment may make great difference in large areas especially in high density residential areas and undoubtedly more people would benefit from such improvements. To increase impervious surface and decrease the inundation area can serve the purpose of decreasing the possibility of city inundation. The improvement can start with the basic strategy of sustainable design that is collecting, storing and reusing. Col lection of storm water in residential area by roof top and pedestrian pavement is a great way. Wuhan's top 20 serious flooding points , about 40% of the total, are located in residential areas which require urgent improvement. Residential area storm water management varies from place to place and climate and site characteristics should be taken into basic design consideration. Rainwater collection can help to solve the problem of flooding and city water logging, whether it is roof rainwater or ground rainwa ter. As for roof rainwater, a simple way is to make use of roof water line and water filtering pipes to lead the clean water to a roof tank. Water collected in this way can easily satisfy the demand for toilet flushing, road cleaning and plants watering. U nderground tanks can be connected to city water supply system to be a source of water, to satisfy the need for industrial production, citizen life and ecological use of water. From the space aspect, changes can be divided into three parts: upper space, gr ound surface and underground facilities. As for upper space like architecture inner building space, green roof and storm water pipe would be the basic improvement. Biofiltration System and small range storm water garden are included in the ground space par t. Underground facilities such as reservoir and water alley also should not be ignored. Creating the green roof collecting facilities may immediately increase the collection area and change the situation. Commonly used strategies include creating vegetate d roofs. Light
46 weight plants and high tolerant plants for drought and temperature variation should be considered. The roof top as one of the open space for architecture could be a great public place, especially for high density residential area. High level residential towers and middle level residential buildings are considered the good targets for implementing this improvement. What's so special about the green roofs is that they have multiple functions. The first is the shading function, as it can decreas e the temperature of the roof. According to reference, green tree shading can reduce surface temperature below plants by 20 45 (11 25 ). Because less heat flows through the roof and into the building, surface temperature will be reduced and this can help t he building stay cooler. In that way, green roof can reduce the energy use of the building they shelter. If certain range of building all have green roofs, the urban heat island effect will be weakened dramatically. Secondly, green surface as an important part of nature can absorb greenhouse gases and reduce the pollution in city atmosphere. With the expanding of constructed areas and increasing demand for green areas in the city, this function of green roofs should not be neglected. Additionally green roo fs can be an open space for people to relax themselves. In many big cities in China green roof area on residential buildings is used as an ideal place for people to grow vegetables and fruits for families. Family roof gardens are now accepted as the health iest way to get daily vegetable supply. Through the development of green roof technology, more choice can be made than before. Generally speaking the local climate may have big influence on the type of vegetation that can grow on the roof top. As a matter of fact, even in the same region the variation of temperature by year may also influence the death rate of plants on the roof top. It has been recognized that the most important function of green roof has to do with storm water run off in the urban environ ment. The green roof can capture most of the rainfalls, though the amount of rainfall that can be caught depends on the density of greenery and the amount of rain fall. Studies show that extensive roofs will typically capture nearly 50 to 100 percent of i ncoming rain, depending on the frequency and amount of rain fall. Also, green roof not only can capture some of the rainfall but also can detain the run off for later release. That's a very important point because it can release the pressure of the water d rainage for the picked time, thus minimizing the community flooding possibility.
47 Biofiltration System as vital part of residential area storm water management is one of the best choices for city facing the similar situation like Wuhan. As part of Low impa ct development this strategy takes the best consideration of environment and it includes steerages like bio retention, green roof , primary filtration treatment such as pervious pavements. Residential biorentention green alley and biorentention basins are usually built between buildings to reduce the run off volume and link the rainwater garden. In newly developed residential areas water management strategies of catching water from roof top and leading water to water storing facilities which are scattered i n the residential area are adopted. In this process the falling water can be primarily cleaned. Then the water goes to infiltration area that can offer larger area for infiltration or bioretention green alley. For residential roadside storm water managemen t, the situation is different. Rainfall may meet three kinds of road surface: impervious surface, green field and pervious pavement, among which the best choice is green filed because the vegetation layer will absorb most of the falling water to supplement underground water. The best arrangement for impervious road is to create road side infiltration alley which can lead storm water to rain gardens and Bioretention basins. Infiltration plants can provide good drainage area for both parking lots and sidewalk s. Many studies have proved that the previous pavements could decrease surface storm water run off. Different choice can be made according to the site situation when choosing pervious pavement. There are four main alternatives for the design for previous pavement: concrete grid pavers, porous concentrate and asphalt, reinforced grass pavement and gravel paving. P orous asphalt as an important strategy for residential area roads has many advantages, for instance, it has been considered as the best management practice for storm water management. The most obvious advantage of porous asphalt is that it is built above the uncompacted subgrade . C lean crush stone in single size are often placed on top layer. A sphalt allowing water to infiltrate down to underground and find it's way to streams , ponds and lakes. The space between sidewalk and street could be vegetation drain alley which create a buffer zone between sidewalk and vehicle road, turf blocks could create private and workable pavement for pedestrians . Swal es are also considered the irresistible part of infiltration area. Area between parking lots can be great choice for the swales. Vegetated swales are now wildly applied as useful design strategy not only because it has various functions for storm water man agement but also it can be
48 made as one of the best places for underground reservoir. Alternative slope could be made for the surface run off. From parking lots to swales, water could be primarily cleaned by the vegetation side in the swales. Overflow drain linked with underground reservoir could enlarge the endurance to face the heavy rainfall. Underground reservoir as a supplement of swales also could be used in places under building for roof water collection and reuse. In that way, the falling water surfa ce run off is reduced. Residential area storm water management still has a long way to go. on the one hand , the capacity sewer system need to be upgraded . Wuhan's sewage disposal system construction started in the early 1984 the standard is too low to aff ord the cities basic needs. On the other hand, most residential area don't have probable stormwater management facility and infiltration pavement that's why city sewer system are under great pressure. Stormwater management in residential area could de desi gned into an water recycle system that links with city drainage sewer and water reused facility. In the collection process, green roof plays an important part, the large amount of water that fall on the roof could be collected directly by green roof and go es to conserve tank by rain pipes. I n the storage cession, underground water reservoir and other water storage facility helps to stagger the peak point of water drainage . W hat's more rainwater that has been primarily cleaned could be reused as green roof i rrigation water and society water usage for daily cleaning and road wash. This whole water cycle could save more water and decrease the inundation directly. Ground rainwater can be valued when best used as Wuhan hosts large squares and developed road syste ms. Wuhan's public squares and roads are mostly asphalt concrete pavement. Ground rainwater can be collected through conducting canals linked to storage facilities. Rainwater on collecting planes near water body can be gathered through natural landscape. A s Wuhan has varied land forms and the scientific design of a collecting system can efficiently conduct the flowing of water to the nearby water bodies such as lakes and rivers. Additionally, lowered green belt or plant covered conducting ditches can be con structed to let rainwater flow through green belt and increase the filtering of rainwater to add to the underground water supply. The filtering of green belt can be helpful in the purifying of rainwater.
49 This picture shows the existing inner Shahu lake a nd the newly developed residential area . this area is an great place for the implication of residence area improvement coopera tion with city public park s . From previous analysis , inner Shahu Lake is shirked because of land use change and city development . One good way to conserve both wetland in the inner Shahu park and manage water here is to buil d stormwater management facility in the near by residential area. Those Green i nfrastructure will collect over flow n storm water to rainwater pipes and biotratio n al ly's then these water will go directly to the rain garden in the wetland locate d in Shahu lake Public park, after days of reclamation and filtration purified storm water could go back to the water container in the near by residential area and be used as toilets flush water or road wash water usage. Till t hen the water could cycle by it self rather then be evacuated by pumping facilities in raining season . The green range with yellow dash is marked as green roof improvement area. In the residence area r ain fall goes directly on the Green Roof, then green roof wi ll kept part of it and the over flow will go to rain pipes first, and the n to filtration pool or the detention cistern under building. Filtration pool will link with small range rain garden in the society. Public park wetland will link with rain garden the over fl ow of rain garden will then go to city sewer. In this way , the infiltration area will be expend ed and wet land near lake will get enough supply of water by link with rain garden, PICTURE 9 Suggested Area for Implement Stormwater Management
50 Storm water management in watershed scale Wetland and watershed is basic unit for water conservation and wild life shelter. According to the statistics presented in the last chapter, lake area has been sharply decreased in the last 20 years. Water pollution and large range of dead fish give the warning that the environment is not healthy and has lost its balance already. Sustainable design based on ecology believes that natural environment offers people certain kind of roles that require their free services and t heir wise actions as a part of the life cycle. Nature endows people with basic services such as keeping fertility of soil, regulating microclimate, adjusting water supply and offering shelter for wild animals and so on. Ecosystem services help sustain huma n life in one way or another. Once the service is destroyed, to restore it to the original state would be much more expensive than maintaining it. Wetland ecosystem as part of the nature assumes an irreplaceable part offering free services to both local pe ople and wild lives. What's more important, lakeside wetland is considered to be one of the very best storm water management area. Wuhan as a city of lakes contains wild range of lakes and wetlands which adjust storm water and microclimate in one way or an other. With the development of the city, the land changes from time to time and this influences many aspects of both human and wildlife. During the city construction and development wetland protection and public park development has been ignored, which lea ds to sever habitat fragmentation and wetland decrease. To protect the existing wetland and rebuild the sensitive area near lakeside could be great ways to manage storm water. To improve and rebuild the natural cycle which has been destroyed new protection wildlife corridor has to be constructed. To prevent habitat fragmentation, storm water improvement strategy should be employed. One of them is to make use of local parks and increase conservation area. According to the existing park map in Wuhan, local pa rks are scattered in the city and most of the public parks are close to lakes. They offer a great opportunity for storm water management and wild life reconstruction. Problem of Wuhan Ã”s public parks are as follows. First of all, water pollution of lakes i s still severe. Secondly, the links between parks and lakes are weak. Thirdly, city parks do not have clear functions of storm water management and ecosystem protection. Some of the parks are isolated in the city. Others are over constructed. For instance, most of the lakeside parks are with hard concrete revetment and others may have enough lakeside green fields but surrounded by construction land and polluted by untreated
5 1 storm water that need to be clean and maintained. To solve those problems, actions a re required in different aspects. Lakeside life belt will be constructed, because this life corridor between the lake and the agriculture fields will preserve the habitat of life species in the lake areas and protect the migratory channel of animals livi ng in the lakes. Additionally, this buffer area can also absorb the nutrient rich pollutants from crop fields, retain earth and reduce soil erosion and protect birds and other wild lives. In order to fulfill the expected functions, the following points wil l have to be followed. First, the buffer belt should be as complete as possible to ensure the totality of the corridor and reduce human interference. Second, life diversity in the lake has to be stressed to ensure the health operation of natural ecology an d healthy interaction between all species in the same environment. Third, local plants will be chosen for the corridor to avoid the introduction of alien species or domestication of wild cre atures. In the process of life belt building, the following step s will be essential: First, right decision should be made on the width of the green corridor. I n the light of the functions of retaining fertility of crop fields bordering on the lake and the nourishing of the habitats of life species in the lake, a width of 10m is usually recommended by experts as it is appropriate and beneficial to the ecological system. Second, efforts should be made to protect the living reeds and calamus and give them the least interference and give their environment preserving capacit y a full play. Third, the local animal species should be protected so that their movements will not be disturbed. F or those animals not so mobile, efforts will be made to restore their favorite surrounding to best enhance their growth and reproduction. For th, it is important to time human handling of creatures in the corridor carefully so that the interference and negative effects on their life will be reduced to the least. In the aspect of park improvement, wet land creation and storm water management mu ch work needs to be done too. Wetland is greatest place for ecosystem recovery and biodiversity protective area. Wuhan, a city with so many lakes and parks don't have even one wetland conservation park. When people talk about park the first thing coming in to their mind is the recreation function of the park. Park designers give the recreation facility and tourist
52 development the first priority but ignore ecosystem management and water conservation, which leads to over construction and too much human interfe rence. The development of Wuhan's conservation park does not have long history. Storm water management function has not been stressed till recent years of park design. City parks have been divided into two types: urban parks and suburb ones. Urban parks in clude comprehensive parks, specialized parks and community parks. Suburb parks include scenic spots, natural protection areas and agriculture parks. Suburb parks are far away from city area and not easily reachable. Urban parks are mostly created for recre ation and cultural functions. To change the situation, more scientific strategies need to be adopted. First of all, links should be created between the green patches in urban areas. Storm water management functions of lakeside parks should be enhanced, la rge infiltration area for nearby community should be created. Small range community rain gardens should have certain green corridor in between both underground and spatially. Wetland should be recovered in lakeside parks and human interference for these we tlands should be reduced to the least. From ecological perspective the better way of conserving wetland is to create better connective corridors with parks so that wildlife can have larger areas to move around. In storm water management perspective, it is better to move preliminary water into larger areas to be purified and reused. Part of the wetland ecosystem services is water reservation and drainage. Secondly, it is a good idea to use greenery and have metal absorption plants for storm water treatment a nd remove bacteria. Untreated rain water could be retreated in the newly constructed wetland areas. Many experiments have been done to treat road run off. Bioretention is one way to remove heavy metals from infiltration storm water. One of the field studie s suggests that the Bioretention is effective with removal of zinc, lead and copper. As a part of the American Low Impact Development green belt near parking lots could help for the removal and management of run off water. Wuan's lakeside parks have simila r vegetation layers, so improving the greenery type is one of the improvement worth trying. According to the statistics of ecological adaptation plants in the wetlands of Wuhan about 137 different type of the wetland plants are local that includes Hygrophy tes 91, Halophytes 11 and Hydrophytes 35 ( Song guangying 2008). Protecting these various types of plants is part of the duty of these wetlands. Some of the plant like Typha angustifolia , Phragmites australis and Nelumbo nucifera are great choice both for wetland water retreatment and value of view.
53 Thirdly, it is important to reform certain stream's curve line and reduce the flow velocity by filter stone. Heavy storm would create large amount surface run off, so it helps a lot to drain away falling water by vegetation ally that can lead water to rainwater garden. From overflow drainage gutter to large drainage area the water could be cleaned the second time by filter stone which size differently from upper stream to lower stream. In large lakeside conserva tion park longer storm water management ally could be created in the wetland side. Successful examples have been created in different parts of the world. In addition, to reduce the human interference of wetland defense and protection contracts should be si gned and identified. Another effective practice is to reduce the hard lake bank to nature riverside and rebuild life cycle of the lakeside both in animal perspective and plant perspective. Additionally, illegal fishing must be banned and local plants shoul d be protected. PICTURE 10 Wuhan Main city park location
54 CHAPTER 7 CONCLUSION Based on the discussion and analysis in the previous chapters, it is easy to see that Wuhan inland inundation and storm water management problems are related to many subjects and require immediate efforts to add ress and tackle. Considering both the city development and nature conservation is an unbreakable rule. To protect what the city has and manage to recover what could be saved is the better choice for the solution. However, it is not enough to find out inund ation points and deal only with the small parts isolated , considering problem in long term perspective with the aim to recycle water in the whole city is the right direction. Water inundation problem is a common problem accompanying the development of the city, to face the problem directly by way of improving the management infrastructure facilities and use bioretention strategies to create more drainage space is a good way to start with. First of all, in the urban planning scope, the improvement of pumpi ng system is indispensable, the maintenance and reconstruction of imperfect sewer system also can't be ignored and to raise storm resistance capacity of sewer system could let the city be prepared for larger thunder storms. Secondly, Lake filling must be r estrained strictly as the problem led by wetland destroy and lakeside water pollution could have severe consequences. Thirdly, implementing of water recycling and rain garden construction should be stressed. In neighborhood scale, the improvement of green roof, detention cistern and other supplementary facilities are needed. These improvements could raise the level of water use efficiency directly. Residential areas are basic unity in city and their large range improvement could make great difference. In ad dition, large range nature water reclaiming area and inner city smaller range rain garden could be constructed. In that way, more infiltration areas are created for the city as supplement of underground water. We can't change the general geographic form of the land but we can control water run off direction purposely by giving little slop between two sides of the road or building Bio retention ally. Watershed as an important part of Wuhan's city development is the link between wildlife, people and nature environment. The watershed changing history reflects not only the development of the city, but also how human activity reforms nature, during which process we
55 see the conflict and compromises between nature and people. Through this process we also see how people and nature are linked together to act as a circle. This thesis analyzes the changing of three lakes both geographically and historically. According to the analysis of the thesis it is effective to use GIS information system statistic to find the be st way to manage and protect the lakeside life cycle and manage storm water sustainably to decrease the possibility of city inundation and inland flooding problem. Water management is linked with land use. During the past 20 year people act as an invasive constructor in nature without considering sustainable development. Urbanization leads directly to lake filling, river blocking, lake bank hardening and wetland destroying. The requirement of economic development and population growth give pressures to gov ernment decision on land use. The disorder of Wuhan's water system is caused by the shrinking of lake area, which can be exemplified by the shrinks of Nanhu Lake and East Lake, in both of which water quality is alarming and large number of fish death still happen every summer. How to control the pollution is always linked with the upgrading of regulations and laws and the effective supervision of the government. The lakeside conservation could start with rain garden construction and wet land recovery in Ea st Lake and Tangsun lake of Wuchang because hardened river banks restrict the natural exchange between land and water. Also it is important to rebuild natural revetment and add storm water management function to ordinary public city parks such as East Lake parkland. All the wet land could be linked with residential areas, for smaller range water conservation parks could release the pressure of urban storm water sewer system. Additionally, larger range water infiltration improvement construction areas are ne eded. According to the statistics of inundation point analysis, inadequate pumping system and construction land in the city are all related to inundation. Wuhan has very high value of storm water reuse by means of green roof collecting and reuse. For insta nce, the residential water management cycle from rain fall to green roof and to rain pipe with Detention Cistern will be both containers and cleaners of water. In the future development of Wuhan's storm water management challenges will still come and the i nvestment of improvement will be huge, so greater efforts will be made to find efficient innovation for water conservation facilities.
56 APPENDIX PICTURE 1 Precipitation of Wuhan from 1962 2012 PICTURE 2 Wuhan's Monthly Precipitation by percentage
57 PICTURE 3 Hubei Province Administrative Region PICTURE 4 Elevation of Hubei
58 PICTURE 5 Wuhan Water body PICTURE 6 Shap e Change of North Lake in Wuhan
59 PICTURE 8 I nundation Point in Wuhan in 2011.6 and 2013.6 Statistic from Wuhan Government PICTURE 7 Analysis of Water inundation point
60 PICTURE 9 Suggested Area for Implement Stormwater Management PICTURE 10 Wuhan Main city park location
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62 Jiri Marsalek , Hans Schreier (2007) Innovation i n Stormwater Management in Canada: The Way Forward . Water quality research journal of C anada . ON L7R 4A6 J ohn Randolph(2011). Environmental Land Use Planning and Management . ISBN: 9781559639484 Hekkert, P. (2006). Design aesthetics": principles of pleasure in design Design aesthetics": principles of pleasure in design. Psychology Science , 48 , 157 Ã 172. Larsen, T. a, Maurer, M., Udert, K. M., & Lienert, J. (2007). Nutrient cycles and resource ma nagement: implications for the choice of wastewater treatment technology. Water Science and Technology": A Journal of the International Association on Water Pollution Research , 56 (5), 229 Ã 37. Li bo, Y. (2010). Investigation of the Civilized and Ecological City Sewerage Engineering, 95 Ã 97. Lundy, L., Ellis, J. B., & Revitt, D. M. (2012). Risk prioritisation of stormwater pollutant sources. Water Research , 46 (20), 6589 Ã 600. Ramlal, B., & Baban, S. M. J. (2008). Developing a GIS based integrated approach to flood management in Trinidad, West Indies. Journal of Environmental Management , 88 (4), Reamy, S. P. (2011). Examining the viability of sustainable practices for a large scale, 1 Ã 80. Shuster, W. D., Burkman, C. E., Grosshans, J., Dadio, S., & Losco, R. (20 14). Green Residential Demolitions: Case Study of Vacant Land Reuse in Storm Water Management in Cleveland. Journal of Construction Engineering and Management , Tortajada, C., & Joshi, Y. K. (2013). Water Demand Management in Singapore: Involving the Public . Water Resources Management . United Nations Global Compact PwC Communication on Progress 2012 U.S. EPA. 2000. Low Impact Development (LID): A literature review. Report EPA 841 B 00 005, Office of Water, Washington, D.C. Williams, Daniel Edward .( 2007 ). Sus tainable design : ecology, architecture, and planning Zhenqiong, W. (2013). Innovate Environment Protection Mechanism in Wuhan Metropolitan Area by Green Insurance, 297 Ã 302. Website : The United Nation Global P ul s e http://www.unglobalpulse.org/projects/BigDataforDevelopment
63 BIOGRAPHICAL SKETCH Rong sheng has four years ' undergraduate study in the major of Environmental Art Design at Chongqing University , which familiarized her wi th the theories of major schools of landscape design and fostered in her the abilities to adapt the theories to suit the given environment for the best aesthetic, ecological, cultural and economic effects. Intense interest and solid foundation in fine arts plus a mastery of basic skills and techniques of sketch, drawing, painting, colors and design visualization enabled her to complete her studies successfully and won the recognition of her professors with several prizes. Believing in continuous learning an d creative thinking, Rong Sheng enter ed Huazhong university of science and technology in 2013 for her Ma ster degree study in Art Design. With a lasting interest in sustainable design, Rong Sheng is currently pursuing her M aster degree in Architecture studi es in the University of Florida with an expected date of graduation in the summer of 2015. She hope s the study in US will prepare her well to stand out in the future competition and in the realization of her dream to become a qualified landscape architect.