NATURAL RESOURCES COMMISSION
Information Bulletin #17 (Second Amendment)
SUBJECT: Floodway Habitat Mitigation
The purpose of this information bulletin is to provide guidance for the assessment and determination of compensatory mitigation associated with an application to the Department of Natural Resources (the "DNR") for a permit under IC 14-28-1
(the "Flood Control Act") or under IC 14-29-1
(the "Navigable Waters Act"). Mitigation may be needed if a construction project is likely to reduce or degrade an existing habitat in a floodway or floodplain. The bulletin assists license applicants with understanding when mitigation is needed and, if so, the type of mitigation that is needed. The bulletin assists the DNR with making licensure determinations. The information bulletin is not a set of inflexible standards. The guidelines are presented with an understanding each parcel of real estate is unique and offers special challenges and opportunities.
The mitigation guidelines are directed most notably to projects that require a permit under the Flood Control Act and rules adopted at 312 IAC 10
to assist in implementing the Flood Control Act. The DNR's permitting responsibilities are within a "floodway" as defined by 312 IAC 1-1-16
and as described in 312 IAC 10
. For purposes of this information bulletin, the "floodway" is limited to where a river or stream has a drainage area of at least one square mile. 312 IAC 10-1-2
(c). The location and delineation of a floodway for a particular river or stream may be obtained from the DNR at:
Division of Water
Department of Natural Resources
402 W. Washington St, Rm. W264
Indianapolis, IN 46204
An overriding concept is mitigation provide similar or better benefits to the resources compared to the impacted area, within the same HUC and preferably within the floodway of the same river or stream and within the same HUC as the project site.
Activities associated with a permit application under the Flood Control Act may require mitigation for impacts upon fish, wildlife, or botanical resources within a floodway. "Mitigation" means actions taken to eliminate, lessen, or replace the loss of environmental benefits and ecological functions and values where those benefits, functions, and values are disturbed by human activities. To obtain a permit, an applicant must prove to the DNR that regulated activities (such as filling, excavating, or building) would not result in "unreasonably detrimental effects upon the fish, wildlife, or botanical resources". IC 14-28-1-22
"Unreasonably detrimental effects upon fish, wildlife, or botanical resources" refers to "damage to fish, wildlife, or botanical resources that is found likely to occur by the director based upon the opinion of a professional qualified to assess the damage and:
(1) creates a condition where recovery of the affected resources is not likely to occur within an acceptable period; and
(2) cannot be mitigated through the implementation of a mitigation plan approved by the director". 312 IAC 10-2-39
Mitigation compensates for detrimental effects upon fish, wildlife, or botanical resources and is often needed to obtain a license. The focus is generally on impacts to a stream and to the riparian habitat that surrounds a stream. Riparian habitat is the land adjacent to a stream that transitions into an upland habitat. Riparian habitat varies in composition based on site conditions, though common components include wetlands, forests, and open and herbaceous areas. Riparian habitats possess various functions and values. They provide vital elements in the overall landscape, such as corridors for a wide range of wildlife and important feeding and nesting areas. Riparian habitats can provide both a buffer and an ecological link between water-based and land-based ecosystems, despite often comprising a small percentage of the total land area.
Before initiating mitigation, the resources in the impact site need to be evaluated. The types, diversity, and density of vegetation, stream characteristics, and proximity to other habitats are examples of characteristics to be identified. Existing ecological condition and performance standards of the mitigation site are based on the best available science that can be measured or assessed in a practicable manner. In some instances, formal habitat evaluation may be necessary. The Floristic Quality Assessment (FQA), Quality Habitat Evaluation Index (QHEI), and Headwater Habitat Evaluation Index (HHEI) are common evaluation tools.
Once a site is evaluated, a strategy is developed following these steps:
(1) Avoidance of impacts to the resources.
(2) Minimization of impacts to the resources.
(3) Compensatory mitigation to offset unavoidable impacts.
During design, seeking avoidance of impacts is the first step. Avoidance is critical if a listed species has been recorded near the project site. Obtaining a list of threatened and endangered species from the DNR's Division of Nature Preserves early in the project development phase can help avoid impacts. For example, avoiding tree cutting at certain times of the year is a means to avoid impacts to the state and federally endangered Indiana bat.
Minimization can occur through a variety of ways. Impacting the edge of forested habitat instead of fragmenting the forest is an example of minimization. Proper scheduling is another form of minimization. For example, in-stream work is scheduled outside the fish spawning season.
Efforts made to restore, enhance, and preserve existing habitat would be considered in evaluating a permit application. Compensatory mitigation should be the last step in mitigation after an applicant has taken appropriate and practical steps to avoid and minimize impacts. Compensatory mitigation offsets impacts to the fish, wildlife, and botanical resources by replacing lost habitat area, functions, and values. This step in the mitigation process typically involves site restoration but can also include creation, enhancement, and preservation.
Restoration is the preferred method of compensatory mitigation and involves restoring habitat in areas that at one time likely contained habitat. Planting native trees, shrubs, forbs, and grasses, and installing in-stream habitat features are common forms of restoration. Restoration is expected to have a higher success rate than new habitat creation, and restoration options should be considered before pursuing alternative mitigation methods. In addition to being where habitat previously existed, restoration adjacent to existing habitat is beneficial for the local environment.
Enhancement generally involves adding natural habitat features within an area that already contains some natural features but may not possess all the desired qualities. Like restoration, enhancement should result in a significant increase in habitat quality. Inter-planting within an area containing some woody vegetation, or removing nonnative, invasive species are examples of enhancement. Under certain circumstances, enhancement may have a negative impact on a current condition for the benefit of another. These instances typically require close scrutiny and detailed explanation of net benefits.
Creation is the construction of a new habitat where not previously existing. Habitat creation may be a difficult and complex endeavor. Understanding the soils, hydrology, and topography of a site will help increase the success of habitat creation. This form of mitigation must be pursued with caution.
Preservation sets aside a piece of existing habitat to avoid impacts by future actions. Preservation is typically part of a mitigation package that includes restoration or enhancement because by itself preservation results in a net loss of habitat. Preservation and creation are typically considered for mitigation only if no other option is available. Preservation is mainly considered in one of the following situations:
(1) Using another form of compensatory mitigation is impracticable at the approved ratio, and preservation would protect tracts with better than average quality that contain at least 10 acres.
(2) Preservation would protect an outstanding resource.
(3) A threat is demonstrated to the resource proposed for protection that is outside the control of the applicant.
III. Mitigation Site Location
A mitigation site should be located within the floodway of the same stream and near the area of impact or at another site within the same HUC. If possible, a mitigation site should be adjacent to existing habitat. Factors to consider in site location include:
(1) Proximity to the impact.
(3) Suitability for protection and maintenance.
(4) Current and probable future surrounding land uses.
(5) Relationships to other natural areas
(6) Hydrology and soils.
(7) Local fish and wildlife populations.
Investigation for suitable mitigation begins within the floodway of the impacted river or stream. Proximity of mitigation to the impact site is often important. Moving mitigation to a different location, but within the same HUC, can be beneficial. For examples, a different location may result in better restoration of lost functions and values or may afford a higher level of protection.
The amount of compensation compared to the amount of impact is the mitigation ratio. The typical unit for the ratio is stated in acres, although linear feet or the numbers of trees may be used. Because mitigation is to offset temporal losses of functions and values and includes a risk of failure, mitigation ratios are generally greater than 1:1. There is typically some loss of functions and values from the impacted site, as well as the risk the values and functions of the original area may not be fully replaced by the mitigation effort. The mitigation ratios presented in this information bulletin are based on restoration and should be considered standard ratios. The DNR may authorize exceptions based upon the impacted habitat. If creation, enhancement, or preservation is used rather than restoration, the DNR would likely seek higher ratios.
|Habitat Category ||Standard Minimum Mitigation Ratio
|Palustrine Emergent Wetland ||2:1
|Palustrine Scrub-Shrub Wetland ||3:1
|Palustrine Forested Wetland ||4:1
|Nonwetland forest (at least one acre of disturbance) ||2:1
|Nonwetland forest (less than one acre of disturbance in a rural area) ||1:1
|Nonwetland forest (less than one acre of disturbance in an urban area) ||5:1 based on trees at least 10" in diameter-at-breast-height
A mitigation ratio may increase or decrease based on factors such as habitat quality and cumulative effects. The ratio would be applied on a case-by-case basis. Habitats may be difficult to mitigate due to uniqueness, rarity, high quality, or difficulty in properly compensating. For example, fens are unique and very difficult to recreate, making mitigation more complicated. Habitat quality can be measured by several site assessment tools, such as FQA, QHEI, and HHEI. The DNR may not approve mitigation for a site with very high quality, such as one with a FQA score of 35 or greater or a mean C-value of 3.5 or greater.
V. Riparian Habitat Mitigation
The level of mitigation for removing trees from a nonwetland, riparian area depends on the size of the area impacted, the number and size of the trees being removed, and the type and quality of the overall habitat being impacted. Impacts under 0.1 acres typically do not require mitigation or additional plantings beyond seeding and stabilizing disturbed areas. Additional mitigation may be warranted if the impact is to a special or unique habitat type. The following consider particular circumstances:
A. At least one acre of nonwetland tree removal
Projects that remove at least one acre of trees in a floodway from a nonwetland area would typically result in a minimum mitigation ratio of 2:1. For example, 1.5 acres of impact would warrant three acres of mitigation. Restoring habitat of this type is slow and difficult. Typical mitigation includes restoring riparian habitat in areas lacking woody vegetation or increasing the size of a current buffer. The applicant submits a mitigation plan to the Division of Water, which is reviewed by a Division of Fish and Wildlife biologist, before the DNR would act upon the permit. The DNR can consider requiring a restrictive covenant or other agreement to better protect the site and ensure the success of mitigation.
B. Less than one acre nonwetland tree removal in rural area
In most cases, a project that impacts less than one acre of trees in a rural nonwetland floodway would result in replanting at a ration of 1:1. The amount of appropriate mitigation may increase if the site is located near a sensitive area or other unique conditions exist. A rural area is generally the area outside:
(A) the corporate boundaries of a consolidated city or an incorporated city or town; and
(B) the territorial authority for comprehensive planning established under IC 36-7-4-205
Often the mitigation can be replanting the disturbed area. If this approach is impracticable, mitigation can be moved off site but within the floodway of a stream at or below the one square mile drainage area. The mitigation would take place along the same stream and close to the area of impact or at another site within the same HUC.
A mitigation plan is not required typically, but a planting plan may be warranted. The applicant submits any planting plan to the Division of Water, which is reviewed by a Division of Fish and Wildlife biologist, before the DNR would act upon the permit. Mitigation would be initiated as soon as practicable and include a mixture of native grasses, sedges, wildflowers, vines, shrubs, and trees suitable to the same region of Indiana (north, central, south) as the mitigation site.
C. Less than one acre nonwetland tree removal in urban area
A project that impacts less than one acre of tress in an urban nonwetland floodway would require replacement of larger trees only. For each tree removed that is at least 10 inches in diameter at breast-height, five trees at least one to two inches in diameter would be planted. Trees are to be selected from the Woody Riparian Vegetation list (Appendix A) and should be planted along the stream corridor, if practicable. If impracticable, a DNR biologist would work with an applicant to devise an acceptable planting plan.
D. Early successional habitat
Early successional riparian habitat typically includes annual and perennial grasses and forbs, and it may include scattered shrubs and small saplings. An example of early successional riparian habitat includes a one-to-five-year-old abandoned farm field. Areas where farming has recently ceased and are fallow for less than a year do not generally require mitigation. Aerial photography or other methods may be used to indicate recent farming activity.
Early successional riparian habitat disturbed by temporary impacts warrants replanting the disturbed area. Mitigation at a ratio of 1:1 would be needed for a permanent impact to early successional riparian habitat. A native herbaceous riparian seed mixture is planted with at least 10 species of native grasses, sedges, and wildflowers selected from the list of Herbaceous Riparian Vegetation List in Appendix A. If the area contains scattered shrubs or tree saplings, mitigation includes woody species native to the region.
VI. In-stream habitat and mitigation
Stream relocations, stream crossings, and other similar projects typically result in impacts upon in-stream habitat that need in-stream mitigation. Because in-stream impacts vary widely, in-stream mitigation is considered on a case-by-case basis. An early coordination meeting with a Division of Fish and Wildlife biologist is highly recommended to review alternatives.
Impacts to less than 50 feet of stream typically do not require in-stream mitigation. Mitigation may be needed if impacts result to important resources, such as mussel beds. Impacts from 50 feet to 150 feet through a single project or an accumulation of projects are to be mitigated 1:1. Impacts over 150 feet warrant 2:1 mitigation. Exceptions to this ration may be requested based on the quality of the habitat impacted and fish and wildlife resources that are impacted and may be reviewed in coordination with the U.S. Army Corps of Engineers and IDEM.
Mitigation for in-stream impacts includes various measures. These measures include the installation of in-stream habitat features, such as boulders or lunker structures; riparian plantings to increase the woody buffer adjacent to a stream; bioengineering along the streambank to reduce erosion; or improving a nearby crossing structure for the benefit of fish and wildlife. Mitigation at 1:1 involves replacing lost functions and values along a length of stream equal to the impact. For 2:1 mitigation, lost functions and values are replaced along a length of the stream or a nearby stream that is twice the length of impact.
Stream relocation projects are complex, difficult to design and construct, and have a high risk of failure. All reasonable alternatives should be considered first. If relocation is still appears the best option, a mitigation plan would be developed. An applicant is encouraged to discuss a stream relocation project with a Division of Fish and Wildlife biologist before submitting an application. Hydraulic modeling of a relocated channel would be calculated with mature trees, shrubs, grasses, and other similar habitat. Additional mitigation, such as planting trees along a stream, may affect hydrologic modeling, so mitigation and engineering design need to be coordinated.
Stream relocation requires replacement of lost qualities and characteristics on the relocated segment, which are at least equal to the original segment, and which fit the surrounding landscape. Natural channel design is applied to the relocated segment, including elements needed to complement upstream and downstream conditions. To the extent practicable, the relocated segment has similar cross-section, substrate, in-stream habitat, and riparian corridor and channel morphology when compared to the original segment. The USDA's Natural Resources Conservation Service provides helpful information on channel design at:
For the relocation of a medium or large trapezoidal channel, a two-stage design may be needed in which there is a low flow channel that is allowed to meander within the new channel. The overbank shelf, or bench is planted with woody vegetation when appropriate. The Woody Riparian Vegetation List in Appendix A includes species appropriate for site conditions.
A stream enclosure uses piping, four-sided culverts, and similar structures that contain a stream on all sides. A stream enclosure is detrimental to fish and wildlife. The DNR typically prefers a bridge or a three-sided culvert instead of a stream enclosure. A bridge or a three-sided culvert helps maintain the natural stream bottom, provides better fish and wildlife movement, maintains essential habitat, and provides resting and feeding locations. A four-sided culvert that is sumped below the existing streambed elevation, to approximate a natural stream bottom, can sometimes be acceptable.
Mitigation for unavoidable in-stream impacts generally requires restoring lost functions and stream characteristics. Planting vegetation along the banks may be suitable mitigation, but often in-stream features are needed. Examples of in-stream features include: restoring riffle-run-pool assemblages; providing slow moving water areas; creating in-stream cover; and making more thorough use of weirs, revetments barbs, boulders, and similar structures.
A complete mitigation plan for impacts to in-stream habitat includes the following:
(1) A plan view of the proposed project.
(2) The materials proposed to be used.
(3) Typical cross-sections.
(4) Typical details for each type of practice used.
(5) The time of year work would be performed.
A. Differing Agency Responsibilities for Mitigation
Mitigation is needed for impacts of at least 0.1 acre to wetlands. The DNR, the U.S. Army Corps of Engineers, and the Indiana Department of Environmental Management have statutory responsibilities for wetlands, but the responsibilities differ. The Army Corps of Engineers and IDEM are concerned with water quality and other issues, but the DNR is concerned primarily with impacts to fish and wildlife habitat. As a result, different factors may be addressed within a single mitigation plan to meet the requirements of the three agencies. Common concerns for DNR are whether wetland mitigation sites have an appropriate suite of native plant species, replace the same type of wetlands as those impacted, provide fish and wildlife resources, and do not create adverse effects to existing resources. The DNR recommends coordinating with all three agencies when developing a mitigation plan.
B. Forested wetlands
Forested wetlands are characterized by woody vegetation that is at least 20 feet tall. Forested wetlands normally have an over-story of trees, an understory of young trees or shrubs, and an herbaceous layer. They are often inundated with floodwater from nearby streams and may be covered by many feet of slow moving or standing water. The numerous benefits provided by forested wetlands, and time needed to successfully mitigate the habitat, warrants a mitigation ratio of 4:1.
C. Scrub-shrub wetlands
Scrub-shrub wetlands may represent a successional stage leading to a forested wetland, or they may be relatively stable communities. Scrub-shrub wetlands are dominated by woody vegetation less than 20 feet tall. They may include shrubs, young trees, and trees or shrubs that are small or stunted because of environmental conditions. These types of wetlands also take time to develop, can be difficult to restore, and typically have a mitigation ratio of 3:1.
D. Emergent wetlands
Emergent wetlands are characterized by erect, rooted, herbaceous hydrophytes (water-loving plants), excluding mosses and lichens. This vegetation is present for most of the growing season in most years. These wetlands are usually dominated by perennial plants and are frequently or continually inundated with water. Marsh, meadow, and slough are types of emergent wetlands. Since some overall loss of functions and values is likely to occur through impacts to an emergent wetland, and there are temporal loses, emergent wetland mitigation is at a ratio of 2:1.
VIII. Planting and Mitigation Plans
A. General information
Depending on the level of impact, projects may need a mitigation plan or a planting plan. A planting plan is generally reserved for projects with reduced impacts, such as less than one acre of nonwetland forested floodway impacts. A planting plan needs to list the species to be planted, the size and number of the stock, and where the plants will be planted. Success criteria and monitoring may be needed with a planting plan. Success criteria and annual monitoring are needed for a mitigation plan. Other elements of a mitigation plan include:
(1) Location of the mitigation site on a topographic or aerial map.
(2) A list of species of native trees, shrubs, and herbaceous plants to be planted.
(3) The number, size, and of location plantings, identified on maps or aerial photographs.
(4) The sources of plants.
(5) The spacing of plants.
(6) The season for planting.
(7) Planting techniques.
(8) Success criteria.
(9) To help meet success criteria, a monitoring plan that extends for at least three years.
(10) If applicable, a plan view and cross-section details of proposed mitigation practices.
Plant species are selected based on local conditions. Planting near adjacent habitat is generally preferred. If an area is prone to flooding, flood-tolerant species are selected that include larger specimens. The taller height of containerized stock increases the probability a portion of a tree would remain above prolonged floodwaters and increases the likelihood of plant survival. Even species with high flood tolerance cannot survive extended periods with their crowns underwater. Areas in the floodway that are less prone to flooding are often suitable to a larger suite of species. An applicant should consider a diversity of trees that produce acorns, nuts, or berries preferred by wildlife. These include oak, hickory, black gum, hawthorn, and dogwood.
Only native species are used for mitigation. Species that are native to Indiana may not be native to the area of a mitigation site. No hybrids, cultivars, or genetically modified plants are used. Lists that include suitable species are in Appendix A. Even though a species may be listed for use within a region of Indiana, local conditions may cause the species to be unsuitable for planting. Species may not be widespread within a region and may have specific habitat requirements. In addition, species may volunteer on a site and do not need to be planted.
B. Woody revegetation
These guidelines apply to designing a mitigation plan or a planting plan that includes woody vegetation. The Woody Riparian Vegetation List in Appendix A includes species native to Indiana that are generally suitable for mitigation. The species approved by the DNR in a mitigation plan or a planting plan become part of the permit. If modifications become necessary to the approved species, a Division of Fish and Wildlife biologist would provide recommendations.
To the extent feasible, woody riparian vegetation is planted with random spacing to simulate natural stocking. By adding or subtracting one foot to the planting distance between every other tree, an offset grid can help give the appearance of random spacing. This approach should be used only with container stock to avoid overcrowding trees. Planting trees and shrubs in rows supports easier mowing and weed management but appears less natural than random planting or use of an offset grid. Tree seedlings or whips should be planted 10 feet apart within each row and 10 feet apart between each row. Ten-foot-by-10-foot spacing yields 435 stems per acre. If container-grown stock (for examples, three or five gallon trees that are four to six feet tall) is used, tree spacing can be 12 feet apart (12-foot-by-12 foot spacing yields 302 stems per acre). Mitigation that involves planting two inch diameter trees can also use 12 foot spacing. These larger specimens often have higher survival rates and restore lost functions at a quicker rate. Most planting plans do not include shrubs but a full mitigation plan does. Additional planting principles include:
(1) At least 10 species are selected from the Woody Riparian Vegetation List that are suitable to the region of Indiana where the project is located.
(2) At least five canopy tree species are selected.
(3) Not more than one maple and at least one hickory and two oak species are selected.
(4) At least 10% of trees are oak and hickory species.
(5) At least five understory tree or shrub species are selected.
(6) Clumping a single species in an area is avoided unless needed to establish habitat features.
(7) A single species comprises not more than 20% of the shrubs and trees planted for mitigation.
(8) Seedlings of selected species are planted in approximately equal numbers.
(9) Shrubs are interspersed between trees and their species are mixed.
(10) Trees and shrubs are planted randomly by species to simulate natural stocking, but including appropriate consideration of wetlands indicator statuses.
(11) Some trees and shrubs are placed within 10 feet from the proposed project limits (such as a fence or access road) to allow canopy closure over time.
(12) Species with a facultative upland (FACU) status are planted in the floodway farthest from the stream or within dryer areas.
(13) Species with a facultative (FAC) or a facultative wetland (FACW) status are placed in the floodway closest to the stream or within wetter areas.
(14) Species with an indicator status of obligate wetland (OBL) are placed in the wettest areas of the floodway
(15) Plants and seeds are obtained from sources within American National Standards Institute (ANSI) Plant Hardiness Zones 4, 5, or 6.
(16) Saplings are planted between either:
(A) September 15 to the earlier of December 15 or until the ground has frozen; or
(B) the latter of March 1 or when the frost leaves the ground in spring to June 1.
(17) Plantings are performed according to sound horticultural practices, including proper planting depth and soil compaction following planting.
(18) Saplings are planted so the root collar is not deeper than 1/2 inch below the ground surface.
(19) The planting area is mowed:
(A) to a height of not more than six inches to provide a suitable planting area generally free of vegetative competition; and
(B) not more than 10 days before saplings are planted.
Upon prior approval by the DNR, a mitigation plan or a planting plan may apply alternative planting specifications.
Results of planting bare-root stock vary depending on site conditions. Spring planting is generally preferred, but the stock may not survive flooding. Planting in the fall may be successful, but frost heaving may displace and kill newly planted seedlings, reduce survival rates, and require replanting. Planting of container-grown stock can occur nearly year-round. As long as bare-root stock is handled properly, survival and growth can be similar to container-grown stock. Planting rates are reduced and wildlife resources tend to be provided more quickly with container grown stock. The use of mulching blankets, erosion control blankets, or turf reinforcement mats helps vegetation become established and reduces erosion during establishment. Fertilizing is not recommended because fertilizer often benefits weedy species. To help protect a mitigation site from unintended disturbance, "Do Not Mow or Spray" or other similar signs may be erected around the perimeter.
If planting trees is part of mitigation, periodic maintenance may be needed to select and maintain the desired species composition. During the first few years after mitigation plantings, mowing when weeds reach 12 to 18 inches can enhance the establishment of trees and shrubs. Mowing should not occur if the area was seeded with a native seed mixture. Tilling around trees should be avoided and herbicides should be used only if necessary and applied according to directions. In areas with high deer density, maintaining taller weeds may prevent seedlings from being eaten, even though seedling growth may be slower. In addition, taller weeds can aggravate damage by mice.
C. Herbaceous revegetation
Almost all mitigation plans require establishing a native, herbaceous layer. A native herbaceous seed mixture includes at least 10 species of grasses, sedges, and wildflowers. These may be selected from the Herbaceous Riparian Vegetation List in Appendix A. They tolerate full sun early in restoration development and persist to form a native understory in forested areas. Tall fescue is not used in a mitigation plan or a planting plan. Tall fescue is toxic to wildlife and most other plant life, including seedling trees. A native herbaceous seed mixture is compatible with native trees, shrubs, and vines and eventually promotes a diversity of food and habitat sources for wildlife. If seeding along a slope of 3:1 or steeper, erosion control mats or similar products provide immediate erosion control and help establish vegetation. Biodegradable materials are recommended when feasible.
Seed may be applied as a total mix or in several passes if species are not compatible during mixing or application. Fertilizer or amended fillers are not be used. Seed may be drilled or sliced into the seedbed, or broadcast mechanically or by hand. Areas that are broadcast seeded need light raking for adequate seed-to-soil contact. Seeds are not be placed more than 1/8 inch deep. Seeds are treated appropriately. Legumes require scarification and others require exposure to cold temperature, also called stratification.
No idle area is left exposed for more than seven days following grading. An area needing temporary cover is seeded with oats from March 15 through June 15 or with winter wheat from September 1 through November 30. Annual rye is also an acceptable species for temporary cover. At other times of the year, an exposed area can be stabilized with erosion control blankets or with a bonded fiber matrix hydro-mulch until seeding.
IX. Mitigation Performance
A. Monitoring Report
For a mitigation plan, annual submission to the DNR of a monitoring report is a permit condition. Most mitigation projects include three or five years of monitoring beginning after a full growing season elapses from the last planting. Ten years of monitoring may be needed for projects that are complex or develop slowly, such as forested wetland restorations. A report may state that mitigation has not begun. A monitoring report is sent to the Division of Water so a biologist may review the initiation, progress, and success of mitigation. If success is not reached by the end of the monitoring period, a new mitigation plan is submitted that includes an extended monitoring period. Action for a mitigation site that has not succeeded may include regrading, replanting, relocation, and any other reasonable initiative to achieve its purposes.
An annual submission for a monitoring report includes:
(1) At least 10 photographs of vegetation.
(2) Identification of the acres planted.
(3) The number of stems planted.
(4) A list of species on-site, including volunteer species.
(5) The estimated survival rates of planted species.
(6) A narrative of the project accomplishments.
(7) Goals achieved.
(8) Plans for the completion of successful mitigation.
A monitoring report submitted to the U.S. Army Corps of Engineers or IDEM may also be submitted as the DNR monitoring report. If the submission does not already include each of the eight elements immediately above, the applicant provides an attachment to include them.
B. Success criteria
Success is based on how effectively a site meets the terms of a mitigation plan. The annual monitoring report describes progress toward meeting the goals, mitigation that is not yet complete, and if there are deficiencies and what is being done to correct them. If the site meets expectations at the end of the monitoring period, the mitigation is deemed successful. The DNR would require additional mitigation and monitoring to correct deficiencies. Success criteria are set forth in the approved mitigation plan.
Measures of success depend on the type of habitat and mitigation requirements. Nonwetland forest mitigation success may be measured in the percent survival of planted trees and shrubs. Typical success criteria are 75% survival of bare-root and 80% or greater for larger stock. Because different impacts and locations result in different spacing requirements between trees, success is based on the percent of planned material that survives. Success can be measured by multiplying the number of trees planted by the percentage of survival. Wetland success criteria involve greater variables, such as:
(1) Density of trees. The DNR would typically seek 75% survival of bare-root, and 80% or greater for larger stock.
(2) The mean vegetative cover after the first year. The DNR would typically seek 80%.
(3) The dominance of native perennial species after five years. The DNR would typically seek 80%.
(4) The absence of highly invasive species such as purple loosestrife (Lythrum salicaria) and common reed (Phragmites australis).
(5) The minimal presence of other nonnative or invasive plant species. The DNR would typically seek coverage not exceeding 10%, including cattails (Typha) and reed canary grass (Phalaris arundinacea).
(6) The percentage of cover of open water or bare ground. The DNR would typically seek less than 20%.
(7) Restoration of the appropriate number of wetland acres determined from a wetland delineation by the U.S. Army Corps of Engineers.
(8) The DNR would typically also seek a native floristic index value of at least 20 and a native mean coefficient of conservatism value (mean C) of at least 3 to 3.5.
A mitigation site not located on public property may need protection of a restrictive covenant to provide a reasonable period for successful plant establishment. The DNR may seek agreement for a restrictive covenant that provides 10 years of protection.
Avoidance: Adverse impacts are avoided altogether through alteration of project location, design, or other related aspects.
Bioengineered: The combined use of biological elements (plant materials) and structural or mechanical reinforcements for stabilization, revetment, or erosion control. Biological and mechanical elements must function together in an integrated and complementary manner.
Buffers: Habitat, typically native plant communities, that separates riparian habitats and wetlands from surrounding land uses.
Compensatory mitigation: The establishment, restoration, enhancement, or protection of ecological functions and values meant to offset those lost through human activity.
Diameter at breast height: The height of a tree measured at 4.5 feet above ground.
Enhancement: The manipulation of the physical, chemical, or biological characteristics of a habitat to heighten, intensify, or improve specific functions or to change the growth stage or composition of the vegetation present. This does not include the increase in habitat acreage and can result in impacts to current conditions.
FQA: Floristic Quality Assessment. Tool to identify the quality of a habitat based on assigned coefficient of conservatism (C) of all plant taxa encountered. The coefficients are ranks of species behavior and represent a confidence level for a taxon's correspondence to anthropogenic disturbances. Coefficients for Indiana taxa have been developed. www.in.gov/idem/ files/fqaindianarprt.doc
Headwater Habitat Evaluation Index HHEI: A rapid habitat evaluation procedure designed for headwater streams and includes physical and biological assessments to determine stream quality.
HUC: Refers to the 8-digit Hydrologic Unit Code Area.
Minimization: In situations where adverse impacts are inevitable, the reduction of impacts to the greatest possible extent through alteration of project location, design, or other related aspects.
Mitigation: Taking action to eliminate, lessen, or replace the loss of environmental benefits and ecological functions where those benefits and functions are disturbed by human activities.
Mitigation Ratio: The ratio of values gained per unit area to values lost per unit area. For example, a ratio of 5 to 1 is equal to five mitigation acres for each acre impacted.
Native: A species known to be historically natural and present at the location and habitat prior to European settlement. Regionally native species that naturally spread into the state following European settlement may also be considered native.
Preservation: The protection of ecologically important habitat in perpetuity through the implementation of appropriate legal and physical mechanisms.
Qualitative Habitat Evaluation Index (QHEI): Tool that combines six metrics based in-stream habitat and surrounding land to gauge a stream's ability to support fish and macroinvertebrate communities.
Restoration: The return of an ecosystem to a close approximation of its condition prior to disturbance; the reestablishment of predisturbance functions and related physical, chemical, and biological characteristics; a holistic process not achieved through the isolated manipulation of individual elements.
Cowardin et al., Classification of Wetlands and Deepwater Habitats of the United States, 1979.
Michigan Floristic Quality Asessment
http://www.npwrc.usgs.gov/resource/2003/ndwetlnd/ndwetlnd.htm (Version 04SEP2003)
Mushet, David M., Ned H. Euliss, Jr., and Terry L. Shaffer. 2002. Floristic quality assessment of one natural and three restored wetland complexes in North Dakota, USA. Wetlands 22(1):126-138. Jamestown, ND: Northern Prairie Wildlife Research Center Online:
Natural Resources Conservation Service Engineering Field Handbook
Swink, F. and G. Wilhelm. 1994. Plants of the Chicago region. 4th edition. Indiana Academy of Science, Indianapolis, IN.
Ward, Andy, Larry Brown, Dan Mecklenburg, and Robert McCall. 2002. Drainage Channel Restoration Construction Project. Department of Food, Agricultural and Biological Engineering, The Ohio State University:
Wisconsin Floristic Quality Assessment
This information bulletin was first published on September 1, 1997 at 20 IR 3546. The Commission reviewed and affirmed the bulletin with formatting changes and the addition of a history section on November 14, 2006. Legislative Services Agency posted the First Amendment on December 13, 2006 at 20061213-IR-312060562NRA
. On July 17, 2012, the Commission approved as the Second Amendment a complete rewriting of the bulletin.
Appendix A -- Mitigation Plant Species
Woody Riparian Vegetation List
| || || || || || || ||
|Common name ||Scientific name ||Region 3 status ||Type of plant ||Tree, Shrub, Vine ||Region (N, C, S) ||Coefficient of Conservatism ||Comment
|Box Elder ||Acer negundo ||FAC ||Large Understory Tree ||T ||N, C, S ||1 ||Only occasionally recommended
|Black Maple ||Acer nigrum ||FACU ||Large Canopy Tree ||T ||N, C, S ||6 ||
|Red Maple ||Acer rubrum ||FAC ||Large Canopy Tree ||T ||N, C, S ||5 ||
|Silver Maple ||Acer saccharinum ||FACW ||Large Canopy Tree ||T ||N, C, S ||1 ||Only occasionally recommended
|Sugar Maple ||Acer saccharum ||FACU ||Large Canopy Tree ||T ||N, C, S ||4 ||
|Ohio Buckeye ||Aesculus glabra ||FAC ||Large Understory Tree ||T ||N, C, S ||5 ||
|Downy Serviceberry ||Amelanchier arborea ||FACU ||Large Shrub ||S ||N, C. S ||6 ||Only occasionally recommended
|Smooth Serviceberry ||Amelanchier laevis ||FACU ||Large Shrub ||S ||N, C, S ||8 ||Only occasionally recommended
|Indigobush ||Amorpha fruticosa ||FACW ||Medium Shrub ||S ||S ||3 ||
|Common Paw Paw ||Asimina triloba ||FAC ||Small Understory Tree ||T ||N, C, S ||6 ||
|River Birch ||Betula nigra ||FACW ||Small Canopy Tree ||T ||N, S ||2 ||
|American Hornbeam ||Carpinus caroliniana ||FAC ||Medium Understory Tree ||T ||N, C, S ||5 ||
|Bitternut Hickory ||Carya cordiformis ||FACU ||Large Canopy Tree ||T ||N, C, S ||5 ||
|Pecan ||Carya illinoensis ||FACW ||Large Canopy Tree ||T ||S* ||4 ||Extreme southwestern counties
|Shellbark Hickory ||Carya laciniosa ||FACW ||Large Canopy Tree ||T ||N, C, S ||8 ||
|Shagbark Hickory ||Carya ovata ||FACU ||Large Canopy Tree ||T ||N, C, S ||4 ||
|Sugarberry ||Celtis laevigata ||FACW ||Large Understory Tree ||T ||S ||7 ||
|Hackberry ||Celtis occidentalis ||FAC ||Large Canopy Tree ||T ||N, C, S ||3 ||
|Buttonbush ||Cephalanthus occidentalis ||OBL ||Medium Shrub ||S ||N, C, S ||5 ||
|Redbud ||Cercis canadensis ||FACU ||Small Understory Tree ||T ||N, C, S ||3 ||
|Alternate-leaf Dogwood ||Cornus alternifolia ||FAC ||Small Understory Tree ||T ||N, C, S ||8 ||
|Roughleaf Dogwood ||Cornus drummondii ||FAC ||Medium Shrub ||S ||N, C, S ||2 ||
|Flowering Dogwood ||Cornus florida ||FACU ||Small Understory Tree ||T ||N, C, S ||4 ||Susceptible to dogwood anthracnose
|Pale Dogwood (formerly Silky Dogwood) ||Cornus obliqua ||FACW ||Medium Shrub ||S ||N, C, S ||5 ||
|Gray Dogwood ||Cornus racemosa ||FAC ||Medium Shrub ||S ||N, C, S ||2 ||
|Red-osier Dogwood ||Cornus sericea (aka (C. alba)) ||FACW ||Medium Shrub ||S ||N ||4 ||
|Hazelnut ||Corylus americana ||FACU ||Medium Shrub ||S ||N, C, S ||4 ||
|Cockspur Hawthorn ||Crataegus crus-galli ||FAC ||Small Understory Tree ||T ||N, C, S ||4 ||
|Downy Hawthorn ||Crataegus mollis ||FAC ||Small Understory Tree ||T ||N, C, S ||2 ||
|Dotted hawthorn ||Crataegus punctata || ||Small Understory Tree ||T ||N, C, S ||2 ||Okay in floodplains; not in extreme southwestern counties
|Persimmon ||Diospyros virginiana ||FAC ||Medium Understory Tree ||T ||S ||2 ||
|American Beech ||Fagus grandifolia ||FACU ||Large Canopy Tree ||T ||N, C, S ||8 ||
|Honey Locust ||Gleditsia triacanthos ||FACU ||Small Canopy Tree ||T ||N, C, S ||1 ||
|Kentucky Coffeetree ||Gymnocladus dioicus || ||Large Canopy Tree ||T ||N, C, S ||4 ||
|Witch Hazel ||Hamamelis virginiana ||FACU ||Small Understory Tree ||T ||N, C, S ||5 ||
|Smooth Hydrangea ||Hydrangea arborescens ||FACU ||Small Shrub ||S ||N, C, S ||7 ||
|Common Winterberry ||Ilex verticillata ||FACW ||Medium Shrub ||S ||N, C, S ||8 ||
|Butternut (White Walnut) ||Juglans cinerea ||FACU ||Small Canopy Tree ||T ||N, C, S ||5 ||Scattered within range; susceptible to butternut canker
|Black Walnut ||Juglans nigra ||FACU ||Large Canopy Tree ||T ||N, C, S ||2 ||
|Spicebush ||Lindera benzoin ||FACW ||Medium Shrub ||S ||N, C, S ||5 ||
|Sweet Gum ||Liquidambar styraciflua ||FACW ||Large Canopy Tree ||T ||S ||4 ||
|Tuliptree ||Liriodendron tulipifera ||FACU ||Large Canopy Tree ||T ||N, C, S ||4 ||
|Wild Sweet Crabapple ||Malus coronaria || ||Medium Understory Tree ||T ||N, C, S || ||
|Black Gum ||Nyssa sylvatica ||FAC ||Large Understory Tree ||T ||N, C, S ||5 ||
|Hop Hornbeam ||Ostrya virginiana ||FACU ||Medium Understory Tree ||T ||N, C, S ||5 ||
|Purple Chokeberry ||Photinia floribunda (formerly Aronia prunifolia) ||FACW ||Medium Shrub ||S ||N ||8 ||
|Black Chokeberry ||Photinia melanocarpa (formerly Aronia melanocarpa) ||FACW ||Medium Shrub ||S ||N, C, S ||8 ||
|Common Ninebark ||Physocarpus opulifolius ||FACW ||Small Shrub ||S ||N, C, S ||7 ||
|American Sycamore ||Platanus occidentalis ||FACW ||Large Canopy Tree ||T ||N, C, S ||3 ||
|Eastern Cottonwood ||Populus deltoides ||FAC ||Large Canopy Tree ||T ||N, C, S ||1 ||Only occasionally recommended
|Swamp Cottonwood ||Populus heterophylla ||OBL ||Large Canopy Tree ||T ||N, S ||8 ||Scattered within its range
|Quaking Aspen ||Populus tremuloides ||FAC ||Small Canopy Tree ||T ||N ||2 ||
|American Plum ||Prunus americana ||UPL ||Small Understory Tree ||T ||N, C, S ||4 ||Also along riverbanks
|Black Cherry ||Prunus serotina ||FACU ||Small Canopy Tree ||T ||N, C, S ||1 ||
|Common Hop-tree ||Ptelea trifoliata ||FACU ||Medium Shrub ||S ||N, C, S ||4 ||
|White Oak ||Quercus alba ||FACU ||Large Canopy Tree ||T ||N, C, S ||5 ||
|Swamp White Oak ||Quercus bicolor ||FACW ||Large Canopy Tree ||T ||N, C, S ||7 ||
|Southern Red Oak ||Quercus falcata ||FACU ||Med.-Lg. Canopy Tree ||T ||S* ||5 ||Far southern and southwestern counties
|Shingle Oak ||Quercus imbricaria ||FACU ||Medium Canopy Tree ||T ||N, C, S ||3 ||
|Overcup Oak ||Quercus lyrata ||OBL ||Medium Canopy Tree ||T ||S* ||7 ||Extreme southwestern counties
|Bur Oak ||Quercus macrocarpa ||FAC ||Large Canopy Tree ||T ||N, C, S ||5 ||
|Swamp Chestnut Oak ||Quercus michauxii ||FACW ||Med.-Lg. Canopy Tree ||T ||S* ||7 ||Far southern and southwestern counties
|Chinkapin Oak ||Quercus muehlenbergii ||FACU ||Med.-Lg. Canopy Tree ||T ||N, C, S ||4 ||Also along well-drained riverbanks
|Pin Oak ||Quercus palustris ||FACW ||Small Canopy Tree ||T ||N, C, S ||3 ||
|Northern Red Oak ||Quercus rubra ||FACU ||Large Canopy Tree ||T ||N, C, S ||4 ||
|Shumard Oak ||Quercus shumardii ||FACW ||Large Canopy Tree ||T ||C, S ||7 ||
|Post Oak ||Quercus stellata ||FACU ||Sm.-Med. Canopy Tree ||T ||S* ||5 ||Seasonally swampy woods in SW counties
|Staghorn Sumac ||Rhus typhina || ||Large Shrub ||S ||N ||2 ||
|Pasture Gooseberry ||Ribes cynosbati ||FAC ||Small Shrub ||S ||N, C, S ||4 ||
|Carolina Rose ||Rosa carolina ||FACU ||Small Shrub ||S ||N, C, S ||4 ||
|Peachleaf Willow ||Salix amygdaloides ||FACW ||Small Canopy Tree ||T ||N ||4 ||
|Sandbar Willow ||Salix interior ||FACW ||Medium Shrub ||S ||N, C, S ||1 ||
|Black Willow ||Salix nigra ||OBL ||Large Understory Tree ||T ||N, C, S ||3 ||
|Elderberry ||Sambucus canadensis (or S. nigra ssp canadensis) ||FACW ||Medium Shrub ||S ||N, C, S ||2 ||
|American Bladdernut ||Staphylea trifolia ||FAC ||Medium Shrub ||S ||N, C, S ||5 ||
|Bald Cypress ||Taxodium distichum ||OBL ||Large Canopy Tree ||T ||S* ||10 ||Only in Vanderburgh, Posey, Warrick, Knox, Gibson Co.
|American Basswood ||Tilia americana ||FACU ||Large Canopy Tree ||T ||N, C, S ||5 ||
|Nannyberry ||Viburnum lentago ||FAC ||Medium Shrub ||S ||N ||5 ||
|Black Haw ||Viburnum prunifolium ||FACU ||Medium Shrub ||S ||N, C, S ||4 ||
|Prickly ash ||Zanthoxylum americanum ||FACU ||Medium Shrub ||S ||N ||3 ||
Herbaceous Riparian Vegetation List
| || || ||
|Common Name ||Scientific Name ||Size / Class ||Indicator
|White Snakeroot ||Ageratina altissima ||wildflower ||FACU
|Hog-Peanut ||Amphicarpaea bracteata ||herbaceous vine ||FAC
|Ground-Nut ||Apios americana ||herbaceous vine ||FACW
|False Nettle ||Boehmeria cylindrica ||wildflower ||OBL
|Blue-Joint Grass ||Calamagrostis canadensis ||grass ||OBL
|Emory's Sedge ||Carex emoryi ||sedge ||OBL
|Shoreline Sedge ||Carex hyalinolepis ||sedge ||OBL
|Lakebank Sedge ||Carex lacustris ||sedge ||OBL
|Larger Straw Sedge ||Carex normalis ||sedge ||FACW
|Hairy-Fruit Sedge ||Carex trichocarpa ||sedge ||OBL
|Fox Sedge ||Carex vulpinoidea ||sedge ||FACW
|Wild or Streambank Chervil ||Chaerophyllum procumbens ||wildflower ||FACW
|Wood-Reed ||Cinna arundinacea ||grass ||FACW
|Honewort ||Cryptotaenia canadensis ||wildflower ||FAC
|Wild Cucumber ||Echinocystis lobata ||herbaceous vine ||FACW
|Canada Wild Rye ||Elymus canadensis ||grass ||FAC
|Bottlebrush Grass ||Elymus hystrix ||grass ||FACU
|Riverbank Wild Rye ||Elymus riparius ||grass ||FACW
|Virginia Wild Rye ||Elymus virginicus ||grass ||FACW
|Boneset ||Eupatorium perfoliatum ||wildflower ||OBL
|Spotted Joe-Pye-Weed ||Eutrochium maculatum ||wildflower ||OBL
|White Avens ||Geum canadense ||wildflower ||FAC
|Fowl Manna Grass ||Glyceria striata ||grass ||OBL
|False Sunflower ||Heliopsis helianthoides ||wildflower ||FACU
|Orange Jewelweed ||Impatiens capensis ||wildflower ||FACW
|Yellow Jewelweed ||Impatiens pallida ||wildflower ||FACW
|Soft Rush ||Juncus effusus ||rush ||OBL
|Wood Nettle ||Laportea canadensis ||wildflower ||FACW
|Rice Cut Grass ||Leersia oryzoides ||grass ||OBL
|White Grass ||Leersia virginica ||grass ||FACW
|Great Blue Lobelia ||Lobelia siphilitica ||wildflower ||OBL
|American Bugleweed ||Lycopus americanus ||wildflower ||OBL
|Virginia Blue Bells ||Mertensia virginica ||wildflower ||FACW
|Hairy Sweet-Cicely ||Osmorhiza claytonii ||wildflower ||FACU
|Switch Grass ||Panicum virgatum ||grass ||FAC
|Wild Blue Phlox ||Phlox divaricata ||wildflower ||FACU
|Clearweed ||Pilea pumila ||wildflower ||FACW
|Green-Headed Coneflower ||Rudbeckia laciniata ||wildflower ||FACW
|Brown-Eyed Susan ||Rudbeckia triloba ||wildflower ||FACU
|Clustered Black-Snakeroot ||Sanicula odorata ||wildflower ||FAC
|River Bulrush ||Schoenoplectus fluviatilis ||bulrush ||OBL
|Soft-Stem Bulrush ||Schoenoplectus tabernaemontani ||bulrush ||OBL
|Dark Green Bulrush ||Scirpus atrovirens ||bulrush ||OBL
|Wool-Grass ||Scirpus cyperinus ||bulrush ||OBL
|Drooping Bulrush ||Scirpus pendulus ||bulrush ||OBL
|Cup-Plant ||Silphium perfoliatum ||wildflower ||FACW
|Late Goldenrod ||Solidago gigantea ||wildflower ||FACW
|Prairie Cordgrass ||Spartina pectinata ||grass ||FACW
|Panicled Aster ||Symphyotrichum lanceolatum ||wildflower ||FAC
|Side-Flowering Aster ||Symphyotrichum lateriflorum ||wildflower ||FACW
|American Germander ||Teucrium canadense ||wildflower ||FACW
|Blue Vervain ||Verbena hastata ||wildflower ||FACW
|Wingstem ||Verbesina alternifolia ||wildflower ||FACW
Plant names and wetland status (Midwest region) from: Robert W. Lichvar and John T. Kartesz. 2009. North American Digital Flora: National Wetland Plant List, version 2.4.0 (https://wetland_plants.usace.army.mil). U.S. Army Corps of Engineers, Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory, Hanover, NH, and BONAP, Chapel Hill, NC. (accessed May 22, 2012)
Posted: 08/01/2012 by Legislative Services Agency
Composed: Jun 26,2017 3:08:46AM EDT
version of this document.