STATUS REPORT ON THE ASSESSMENT OF
WETLAND CREATION FOR MITIGATION IN THE SJRWMD
Department of Resource Management
St. Johns River Water Management District
P. O. Box 1429
Palatka, Florida 32178
11 November 1992
TABLE OF CONTENTS
. . . . . . . 3
ASSESSMENT AND COMPLIANCE PARAMETERS .......................... 4
Permit conditions and project design ................................ 6
Site evaluation ................................................. 8
Corrective measures needed ....................................... 9
Success criteria ................................................. 10
Com pliance .................................................. 12
Related Assessment Information ....................................12
DISCUSSION AND CONCLUSIONS
Creation assessment .............
Future considerations ............
Figure 1. Frequency bar chart of creation sites by county.
Figure 2. Percentage bar chart of inspected creation sites by
Figure 3. Percentage bar chart of creation site areas (acres).
Chart intervals are midpoints, except intervals 1
and 10 which include areas less than 0.5 and greater than 10.5
Figure 4. Percentage bar chart of site age (in months) at time of field
inspection. Chart intervals are midpoints.
Appendix A Mitigation assessment and compliance data forms.
Case examples of wetland mitigation.
The District considers mitigation for wetland impacts under it's Management
and Storage of Surface Water rule (chapter 40C-4 F.A.C.), and also as part of the
Wetland Resource Management Program (chapter 17-312 F.A.C.), delegated from the
Department of Environmental Regulation to the District in October 1988. Between
December 1983 and August 1992, the District issued 6,690 Management and Storage
of Surface Water (MSSW) permits and 940 Wetland Resource Management (WRM)
permits. Mitigation for wetland impacts was required for 1,096 of these permits
including 871 MSSW permits (13% of all MSSW permits) and 225 WRM permits (24%
of all WRM permits). The distribution, by county, of permits issued with mitigation
is shown in Figure 1.
Wetland creation is one of the mitigation alternatives under both of these rules.
Other possible mitigation measures include wetland enhancement or restoration and
the preservation, by conservation easement or fee simple title transfer, of both
wetlands and uplands. Of the issued permits which entailed mitigation, the vast
majority involved wetland creation either as the sole mitigative measure or combined
with another mitigation alternative. Since "wetland creation" has been so prevalently
used as a method to off-set wetland impacts, the phase has often been erroneously
used interchangeably with the term "mitigation".
Wetland creation is basically the transformation by construction techniques of
uplands (as defined under the rules) to wetlands. Typically, the site is first graded to
the appropriate elevation, i.e., the elevation which will be inundated or saturated at
duration and frequency necessary to support the target vegetative community. The
site is then usually planted with the appropriate species.
While forested wetland creation typically requires planting, some herbaceous
creation efforts have employed natural re-colonization through the transfer of
wetland organic mulch as a supplement to or in lieu of plantings. The success of a
created wetland depends on a suite of factors including elevations for grading and
planting, soil preparation, viability of plant materials, planting techniques and
The extent and type of wetland creation required to offset adverse effects of a
specific project depend on an evaluation of the individual site. The ratios of created
to lost wetlands are generally greater for forested than herbaceous systems due to the
longer period required for replacement and the greater difficulty in creating forested
In 1988 the District staff initiated an evaluation of permitted wetland creation
sites. This wetland creation evaluation is on-going and is in addition to the District's
overall compliance program which has been in effect since the inception of the MSSW
Rule and delegation of the WRM Program. Staff has intensified this study during the
past two years.
Staff has inspected 326 wetland creation sites as of August 1992 which
represent 265 permits that were issued between 1986 and 1992. Some permits entailed
construction of more than one creation site, therefore the inspection results will
always indicate a greater number of individual creation sites than permits involving
The types of wetland creation inspected to date include freshwater herbaceous
(38%; 349 acres), freshwater forested (57.4%; 561 acres), saltwater herbaceous (3.4%;
46 acres) and saltwater forested (1.2%; 10 acres). A total of 966 acres of wetland
creation, or 25.6% of the total acres of wetland creation that were permitted through
September 1991, have been inspected to date (Figure 2). All of the permitted acreage
has not yet been constructed as construction has not commenced on many permitted
Staff has developed a mitigation database which contains the assessment
information for the mitigation projects and acts as a recordkeeping tool. The first step
of current mitigation assessments is an administrative review to determine
requirements for, and compliance with, recording of legal documents, submission of
monitoring reports and as-built surveys etc. The administrative review is followed by
a site inspection to evaluate compliance with permit conditions and permitted plans
and other aspects of the site such as the "success" of the mitigation effort and
techniques employed in the construction. The content of the database has evolved
through this effort to include more detailed and relevant information. Information
from both steps is entered into the tracking portion of the database in order to
facilitate follow-up and monitor mitigation compliance.
The mitigation database is intended to eventually serve several goals: (1) to
provide an up-to-date summary of mitigation compliance actions and a framework
for effective enforcement; (2) to answer specific questions relating to design and
permitting of future wetland creation projects; and (3) to provide information
regarding long-term viability and wildlife values of mitigation efforts. Although the
database is designed to contain information for all types of mitigation, wetland
creation sites encompass the majority of those inspected to date.
ASSESSMENT AND COMPLIANCE PARAMETERS
Observations included the design criteria specified in the permit conditions
and plans, compliance information, corrective measures necessary, vegetation
survival, coverage, and characterization, and evaluation of the success and wildlife
value of the created wetland (see Appendix A).
The "compliance with permit conditions" category was a general determination
as to whether or not the creation site was built in accordance with the permitted plan
and met all of the conditions of the permit. Included in this determination were
administrative reporting requirements and site construction requirements.
Five categories of remedial measures which may be necessary were recorded.
These included regrading the site, replanting, stabilization, removal of exotics, and
The creation site was evaluated as to whether or not the success criteria
specified in the permit conditions and approved mitigation plan had been met.
Success criteria typically include a specified survival of plantings and percent
vegetative coverage. A final determination of success is generally made three to five
years after planting.
The District has included wildlife value and similarity evaluations in the
mitigation assessment in order to include information on those creation efforts which
may be a low priority for, or not require, corrective action because they are
functioning as viable wildlife habitat albeit perhaps of a type different than that
anticipated when the permit was issued and success criteria specified.
Wildlife value of the creation site was judged for its current value, potential
value, current similarity to the value intended in the permitting action, and the
long-term potential to provide wildlife value as intended in the permitting action.
Current wildlife value was ranked as low, medium or high based upon
observed or reasonably expected use of the site by fish and wildlife. Potential wildlife
value was similarly ranked in order to determine whether the value of sites was
likely to improve or decline as they matured and the surrounding landscape changed.
For the purposes of this assessment "potential" was a projection of about 20 years.
Current similarity to the intended value was an assessment of whether the site
provides the general type of habitat intended in the permitting action for example
"broad-leaved marsh with open water feeding pools", or "early successional
cypress/mixed hardwood forest". Potential similarity was an assessment of the
potential of the site to provide the type of habitat anticipated in the permit, i.e., are
the basic components (hydrology, grade, plantings and location) sufficient to allow
successional development into a functional wetland of the type intended in the
The wildlife value section has recently been revised to account for factors
external to the physical design, particularly those related to current and future
surrounding land use. The wildlife value and similarity also has recently been revised
from a three-point (high, medium, low) scale to a five-point scale to record more
precise information and improve the analysis. A staff training and evaluation
standardization effort is concurrently being implemented to verify the quality of the
wildlife evaluations. The information collected to date should be considered only as a
compilation of individual staff assessments until the sites are re-evaluated under the
Correlation between the current and potential wildlife value, functional
similarity to the permit intent and various aspects of the design and construction is a
key element of the database design. Results will be reported when sufficient data are
available for statistical analysis.
Permit conditions and project design
Wetland creation plans submitted by the applicant were referenced by 87.1% of
the permits. The remaining 12.9% of the permits had conditions which committed the
permitted to create a specific type of wetland.
A planting scheme was submitted by the applicant with 71.4% of the permit
applications. The planting scheme is basically a plan detailing the species of plants,
the number of each species to be planted and the location on the site where each
species should be planted. The 28.6% of the permits that did not include specific
planting schemes fell into three additional categories: natural recruitment and
succession following grading and transfer of wetland organic topsoil (mulch),
specification of planting details by permit condition, and those projects which had no
details for planting either submitted with the application or required by permit
condition. The latter category primarily includes the earliest permitted creation
Mitigation specific as-builts were required for 58.4% of the permits inspected
to date; as-builts have been received for 47.5% of these permits. A portion of those
that were not received were due to confusion between this requirement and the
as-builts which have been traditionally required to satisfy those aspects of a project's
construction that were designed by a Professional Engineer.
Success criteria (i.e., a specified survival and coverage of plantings within a
specified time period) were included by permit condition for 89.4% of the permits.
Maintenance procedures were specified for 60.1% of the permits. Exotic and
nuisance species control measures were specified for 80.1% of the permits.
Contingency plans were specified for 77.3% of the permits.
Monitoring reports were required for 84.6% of the permits; reports have been
submitted for 58.8% of the these permits. The level of information in the reports is
As partial mitigation, or to protect the wetland creation areas, conservation
easements or deed restrictions over the mitigation areas were required to be recorded
for 39.4% of the permits; proof of recording has been received for 58.1% of these
Various features of the project site were evaluated to determine whether the
construction was in general accordance with the approved mitigation plan.
Correct wetland type is a rough determination as to whether or not the
mitigation effort successfully created the general type of the target wetland for
example, cypress dome, mixed hardwood floodplain, broad-leaved herbaceous marsh.
The type of wetland created was as intended by the plans and permit conditions for
95.7% of the herbaceous and 87.5% of the forested freshwater sites. All of the
saltwater sites were constructed as the type intended.
Size of the creation site was recorded as being correct for 90.2% of all sites,
including 90.1% of the herbaceous and 89.3% of the forested freshwater sites. All of
the saltwater sites inspected were considered to have been constructed to the correct
size. The majority of the creation sites are less than 1 acre, as can be seen in Figure 3.
Grading was considered correct for 78.0% of all sites, including 88.3% of the
herbaceous and 68.4% of the forested freshwater sites. All saltwater sites were
considered to have been graded correctly.
Correct species were used in the plantings for 84.4% of all sites which had
specific planting requirements. By category; correct species were used in 88.6% of the
herbaceous and 79.9% of the forested freshwater sites. Correct species were used in
all saltwater sites. In general, sites which were not indicated as having correct species
either lacked one or more of the species specified in the permit, or no planting had
been performed on the site (both cases would represent sites which were not in
Planting elevations were considered correct for 78.7% of all sites, including
86.4% of the herbaceous and 71.8% of the forested freshwater sites. All saltwater sites
were considered to have been planted at correct elevations. "Correct" here is an
opinion as to whether or not the plants were planted at the appropriate elevation to
promote their growth and continued survival, rather than a determination or
measurement as to whether they were planted at a specific elevation per the
permitted plans or conditions.
Sites were indicated as having been properly stabilized (i.e., having sufficient
natural or artificial cover such that erosion and sedimentation would be unlikely to
occur) for 82.2% of all sites, including 85.8% of the herbaceous and 88.9% of the
forested freshwater sites. One herbaceous saltwater site was not stabilized.
The requirement for mulch, hydrologic monitoring and plant inventories,
either as a permit condition or approved creation plan, was not recorded on the data
form until recently.
Corrective measures needed
Due to the design of an earlier version of the data forms we cannot determine
whether "considered necessary" for these categories means "needed to create a viable
wetland" or "needed to comply with the requirements of the issued permit".
However, this clarification will be available for future evaluation. The results
presented here should be considered solely as staff opinions as to what is needed on
the site rather than as a summary for compliance purposes.
Maintenance, i.e., site stabilization, replanting, nuisance species removal, and
trash removal, was considered necessary, although not always required by permit
condition, for 44.6% of all sites including 41.7% of the herbaceous and 48.8% of the
forested freshwater sites. Maintenance was also necessary for two saltwater sites.
Maintenance was known to have been performed on 50.0% of all sites
including 59.4% of the herbaceous and 41.6% of the forested freshwater sites.
Replanting or supplemental planting was considered necessary for 42.4% of all
sites including 24.6% of the herbaceous and 58.1% of the forested freshwater sites.
One forested saltwater site needed replanting.
Regrading was considered necessary for 19.8% of all sites including 10.7% of
the herbaceous and 28.8% of the forested freshwater sites.
Nuisance species control was considered necessary for 39.9% of all sites
including 29.9% of the herbaceous and 48.9% of the forested freshwater sites. One
herbaceous and one forested saltwater site also required nuisance species control. The
type of exotic or nuisance species was not recorded, but cattails (Typha spp.) and
brazilian pepper (Schinus terebenthifolia) are major problem species on some sites. In
addition, invasion by upland species occurred on the drier sites affected by the
Success criteria are evaluated regularly, with a final determination usually
made at three to five years. The success criteria had been met for 27.1% of the
herbaceous and 8.8% of the forested of the freshwater creation sites which had been
established for the time frame specified in the success criteria. A cross-tabulation of
sites that failed to meet the permit success criteria with other variables in the
database indicates that the primary reason for low success rate is the need for
additional plantings (85.3% for forested sites). A need for maintenance appears to be
the secondary contributing variable. Two-thirds (66.7%) of the saltwater sites had met
the specified success criteria. Nearly one-half (48.5%) of the sites had, at the time of
inspection, not been established long enough to determine success. The distribution of
creation site age at the time of the inspection is shown in Figure 4.
The long term potential of the site to meet the success criteria both with and
without additional compliance action by the District was also evaluated. About half
(59%) of the sites were judged to be likely to meet the success criteria in the long
term without additional action; 83% of the sites were judged likely to meet the
success criteria with additional action by the District and the permitted. The cause of
the remaining 17% that are unlikely to meet the success criteria, even with action,
was not recorded, however it is likely that these sites fall into two categories: a) those
sites that are a functional wetland type different than that which was permitted and
for which District enforcement action would serve no purpose and b) those sites for
which the original design was inappropriate or for which the original design cannot
be implemented due to conflicting physical constraints of on-site construction or
other factors. The latter category of projects will require permit modification in
addition to other corrective actions.
Compliance was evaluated at the permit level (i.e., for 265 permits) and also at
the site level (i.e. for 326 sites which represent the 265 permits). Two-thirds (63.7%) of
the permits inspected to date are not in compliance with all administrative
requirements and half (56.6%) of the sites are not in compliance with all construction
requirements. At the individual mitigation site level, compliance (i.e., meeting all
permit conditions applicable at the time of the inspection and constructing the site in
accordance with the approved plans) was 43.4% for all sites including 57.5% for the
herbaceous and 31.7% for the forested freshwater sites. Compliance for saltwater sites
It is important to note that the percentage of projects in compliance is greater
than the percentage of projects meeting the success criteria because the success
criteria determination is made after a three or five year period of time. Until that time
period is met the success criteria condition is not a part of the compliance
As of August 1991, enforcement letters had been mailed to 48.6% of permit
holders with known compliance violations. Most of the remaining permittees have
been contacted by telephone. A follow-up field visit was scheduled for 50.7% of the
permits to inspect site progress.
Related Assessment Information
Data were recorded for several factors that are not part of the permitting
process or requirements. These data will be used in future studies to evaluate other
factors contributing to wetland creation success.
Siting contiguous to an existing wetland was 54.6% for all sites, and
substantially more common for forested (70.0%) than herbaceous (27.4%) wetland
creation. Use of the site as a stormwater treatment area was more common for
herbaceous (71.4%) than forested (36.0%) creation. Permitting the use of created
wetlands for stormwater treatment was more common in the earlier issued permits.
Soils information was submitted with 44.6% of the permits. Mulch was known to
have been used in a minority of both herbaceous (19.0%) and forested (28.8%) sites,
although actual use was probably higher.
More than one-half (54.1%) of the creation sites had wildlife value similar to
that anticipated at the same point in time by the permit action. The current wildlife
value was considered at least moderate for 58.4% of the herbaceous and 37.1% of the
forested freshwater sites. The potential for the sites to achieve, without enforcement
action, wildlife values similar to that anticipated by the permit action was considered
moderate or high for 80.2% of the herbaceous and 63.8% of the forested freshwater
sites, 75.0% of the saltwater sites, and 59.3% of all creation sites.
Hydrological problems external to the permitted design, such as drought, can
contribute to lowered achievement of success criteria and wildlife values, particularly
in the short term. Hydrological problems were noted for 21.4% of the herbaceous and
38.9% of the forested freshwater sites. The difference between herbaceous and
forested sites is likely due to the more narrow range of hydrologic tolerance of the
planted woody species, particularly the more transitional species.
The wildlife results suggest that freshwater wetland creation is a viable
mitigation option. Recent additions to the mitigation assessment parameters, which
will allow a comparison of success rates depending upon siting of the mitigation
areas, are expected to indicate that location is a key factor in long-term success.
Additional emphasis on the appropriate siting during the permit review and project
planning process would likely increase the overall effectiveness of mitigation efforts.
As anticipated, saltwater creation sites appear inherently more successful than
freshwater sites, and forested freshwater creation appears more difficult than
herbaceous creation. The contrast between freshwater and saltwater systems may be
attributed to data available in the design of the system. Saltwater system design is
based upon established and recorded tidal ranges usually from gaging stations in the
immediate area. The design grade of freshwater systems is usually based on adjacent
wetland grades without extensive knowledge of existing hydroperiods. Only
occasionally have fresh water levels been recorded over sufficient time that design
can be based on historic data.
The data also indicates a difference between forested and herbaceous systems
in the correctness of grading. It is likely that design of forested system grading and
hydrology should include more detailed evaluation of the pre- and post-development
drainage basins (a water budget) and the duration, frequency and seasonality of
inundation. For certain types of forested systems, particularly the more transitional
areas, a number of other factors such as physical and chemical soil properties and
mycorrhizal relationships, are probably as critical as hydrology in determining
Drought conditions over much of the District often made a field determination
of correctness of grade difficult for freshwater systems particularly when there was
not an adjacent natural wetland for comparison. It should also be noted that the
"correct" hydroperiod of created freshwater systems can be difficult to determine
during a one-day site inspection as most freshwater system water levels fluctuate
seasonally and following storm events. During a field inspection in saltwater systems,
the evidence of tide fluctuations is readily observable and "correct grading" is a more
Correct planting elevation is often, but not always, a function of grading. In
some instances, drought conditions again contributed to difficulty determining
whether the plants were planted at the correct elevation. For this parameter the
remaining sites that were not indicated as having correct planting elevations either
had species clearly planted at elevations which would not support their continued
survival and growth or the reviewer was unable to determine if the plants were
planted at the correct elevations.
Requiring mitigation as-builts and planting inventories as standard permit
conditions will improve the evaluation process. Results of an earlier mitigation
assessment indicated the need for submittal of a mitigation specific as-built survey in
order to determine whether the size, grading and planting elevations were in
accordance with the permitted design. This requirement has been included on most
permits issued since 1989. In the absence of an as-built survey, observations of
correctness of grading and size, were not measurements, but rather estimates. In the
case of grading, the estimate was largely based upon whether the hydrology was
correct. If the hydrology appeared correct the assumption was made that the grading
Mitigation planning and permitting requires a regional perspective to ensure
that cumulative and secondary impacts to an ecosystem will be capable of being
offset in the long term. There are instances where regional mitigation efforts
(mitigation banks) between a number of parties can be effectively used to ensure a
greater likelihood of long-term success and to address secondary and cumulative
impacts. The evaluation of a banking proposal should be based on the same criteria
as other mitigation proposals.
Wildlife value results should be considered preliminary at this time. It is
anticipated that the evaluations, although subjective, can be useful for comparing the
actual and potential result of the creation effort with that anticipated at realistic time
frames during the permit review process. It is recognized that the current
quantitatively based success criteria do not allow for the assessment of the variability
inherent in natural systems, nor do they allow for a broader functional assessment
based professional ecological judgement. Further assessment will likely also lead to
an acknowledgement that wetland acreage comparisons (lost vs. created) are not a
representative measures of the impact of a project or of the effectiveness of a
Wetland creation is a relatively new science. Some of the early creation efforts
which were "successful" were due mostly to luck and natural ecological succession.
Many sites were not "successful" resulting in the conclusion that creation does not
work. It is unfortunate that the nature of a regulatory program requires a short-term
assessment of impacts and compensatory mitigation. This has caused the cost of
creation to increase in an effort to accelerate natural succession and quickly reach a
point at which the permitted can be released from responsibility for the creation
effort. Additional research is needed to evaluate the ecological succession of
man-made systems. With proper planning and reasonable expectations this can occur
as a part of the regulatory process.
Long-term assessment of creation will likely show that if properly designed
and implemented it can be used in combination with other mitigation alternatives
and a responsible site plan to effectively offset many of the adverse effects of impacts
to wetlands. Mitigation, like other permitted systems, requires a long term
commitment from both the permitted and the District.
The percentage of projects that are in compliance is higher than previously
reported by other agencies who have assessed their mitigation program. The higher
compliance rates within our District are thought to be directly related to a higher
level of staffing which allows for more oversight and assistance. Administrative
compliance is expected to improve as a result of the recently implemented permit
condition tracking aspects of the mitigation database. Prompt site follow-up will
identify problems early rather than late in the monitoring time frame, minimizing
compliance cost and effort for both the District and permitted.
When a project is not in compliance, there is usually a combination of
administrative and site problems. Noncompliance with permit conditions ranges from
late submittal of a monitoring report to improper site construction and planting. The
degree of enforcement action required to achieve compliance will, therefore, vary
considerably among permits. In addition, there is a range of effort associated with
enforcement, depending on the severity of the compliance problem. Many permits
require relatively minor administrative action such as a reminder phone call of a
past-due monitoring report. Other permitted projects have more serious problems
that require follow-up, such as site stabilization, exotic or nuisance species removal,
or replanting. Some will require substantial action such as construction or re-design
of the mitigation site.
Two-thirds (63.7%) of the 265 permits requiring mitigation reviewed to date
are not in compliance with all administrative requirements and half (56.6%) are not in
compliance with site construction requirements. Although these figures indicate that
wetland creation will require additional effort, it should also be noted that the rate of
non-compliance for mitigation projects is not substantially different than for other
types of projects which the District regulates.
Less than 20% of the projects inspected to date have met the success criteria
specified in the permit. More than half (59.3%) of wetland creation sites, however,
demonstrate the potential to succeed as functioning wetlands with at least moderate
wildlife value without enforcement action. This discrepancy suggests the need for a
review of the success criteria placed on mitigation permits. Some possible
modifications include a requirement for an "interim" determination of the likelihood
of success and also a re-evaluation of the density requirements for plantings.
The mitigation database provides the opportunity to develop statistical
answers to questions as the number and age of projects increases. Answers to the
following and other questions will have a large effect on mitigation compliance and
success, and on the cost of wetland mitigation to permittees and the District.
1) What is the effectiveness of early post-construction follow-up of the creation
site? Mitigation projects are now added to the database tracking system as they are
permitted and receive early follow-up, whereas the follow-up was later for many
older projects. A comparison of these two groups of projects can provide the required
2) What are the critical design factors contributing to long-term success of
wetland creation sites? A cross tabulation of design factors and "success" measures
can provide an answer.
3) What is the efficiency of added effort in increasing the compliance of
projects? The number of field visits and compliance actions are entered into the
database. A numerical tabulation of these efforts can be cross tabulated with "success"
4) What are the likely improvements to mitigation in the review and
permitting process? Wetland creation designs that demonstrate lower probability of
long-term success or other problems can be discouraged during the review process or
more thoroughly conditioned in the permitting step.
The database will provide an essential design element in an unbiased
comparison of wetland creation and restoration and enhancement banking. The
database is currently tracking these other forms of mitigation as well as preservation
of wetlands and uplands. Planned future reports will continue to assess wetland
creation in addition to other mitigation alternatives.