DEPARTMENT OF ENVIRONMENTAL PROTECTION Bureau of Water Quality Protection DOCUMENT NUMBER: 363-0300-001 TITLE: Design Criteria - Wetlands Replacement/Monitoring EFFECTIVE DATE: February 11, 1997 AUTHORITY: The Dam Safety and Encroachments Act, Act of November 26, 1978, P.L. 1375, as amended, P.S. 693.1 et seq. POLICY: DEP provides both general guidance and specific recommendations concerning the design and construction of replacement wetlands to environmental professionals engaged in such work. PURPOSE: DEP provides both general and specific guidance to environmental professionals who are engaged in the design and construction of replacement wetlands to maximize the success rate of replacement wetlands as required by the Chapter 105 Rules and Regulations. APPLICABILITY: This policy applies to all persons engaged in the design and/or construction of replacement wetlands. DISCLAIMER: The policies and procedures outlined in this guidance document are intended to supplement existing requirements. Nothing in the policies or procedures shall affect regulatory requirements. The policies and procedures herein are not an adjudication or a regulation. There is no intent on the part of the Department to give these rules that weight or deference. This document establishes the framework for the exercise of DEP's administrative discretion in the future. DEP reserves the discretion to deviate from this policy statement if circumstances warrant. PAGE LENGTH: 11 Pages LOCATION: Vol. 34, Tab 18 NOTE FOR WORLD WIDE WEB USERS: If you desire paper copies of any policy document, you may order from DEP s Policy Office at 717-783-8727. 363-0300-001/February 11, 1997/Page 1
DESIGN CRITERIA FOR WETLAND REPLACEMENT A guidance document prepared by the Pennsylvania Department of Environmental Protection for use by Environmental Professionals in planning and preparing Wetland Replacement Plans in the Commonwealth of Pennsylvania. Introduction: This guidance document is intended to provide direction to environmental professionals responsible for preparing wetland replacement plans pursuant to The Clean Streams Law, The Dam Safety and Encroachments Act, and companion Chapter 105 Rules and Regulations (as amended). This document identifies and explains the controlling parameters in wetland replacement and identifies basic documentation needed to complete a replacement plan. The level of detail of information required and degree of pre-preparation study is dependent upon the site in question, and is generally proportional to the size of the replacement system. This manual does not present a "cookbook" approach to wetland replacement, nor should it be viewed as such; but merely guidance as to the general detail and specificity of information needed to prepare and implement a wetland replacement plan. The technology of wetland replacement is rapidly evolving and the Department of Environmental Protection will accept new methodologies so long as reasonable assurance is provided that new techniques and methods will culminate in the desired outcome; a functioning and self-sustaining replacement wetland. Any questions concerning the content of this manual should be directed to the Division of Wetlands Protection. 363-0300-001/February 11, 1997/Page 2
I. Statutory Authority The Department is authorized through Sections 105.18a(7) and (7) of the Chapter 105 Rules and Regulations, 25 Pa. Code Chapter 105, to require construction of replacement wetland resources to compensate for unavoidable wetland impacts as a result of permitting actions or as a measure to mitigate the effects of violations. Section 105.20 provides the general criteria for wetland replacement actions. II. General Requirements Section 105.20a of the Department's Chapter 105 Rules and Regulations mandates the following minimum criteria for wetland replacement: A. Wetlands shall be constructed at a minimum area ratio of 1:1; replacement acres to affected area. B. Functions and values (herein with function(s)) that are physically and biologically the same as those that are lost shall be replaced at a minimum ratio of 1:1. C. For structures constructed, or activities undertaken without a permit, the wetland shall be replaced at a minimum of 2:1 area and function ratio. D. Replacement wetlands shall be located adjacent to the impact site unless an alternative location is approved by the Department. III. Replacement Criteria A. Size The replacement wetland shall be of such size that it equals or exceeds the area of wetlands which will be impacted by the proposed action; and that it replaces, to the maximum extent practicable based upon available technology, the wetland functions which will be lost as a result of the action. Under normal circumstances, the Department will require a 1:1 area and function replacement ratio. However, in situations where a 1:1 ratio will not result in the re-establishment of a wetland system which functionally or ecologically equals or exceeds that which will be impacted, or where the construction of a replacement wetland system will nonetheless result in a short or long term negative environmental impact, the Department may require a ratio greater than 1:1 to offset that impact. Specific examples include, but are not limited to: replacement of forested wetland systems; replacement which will not occur concurrently with permitted activities; and replacement at a location not adjacent to the impacted area. 363-0300-001/February 11, 1997/Page 3
Additionally, the Department will require that wetlands be replaced at a 2:1 or greater ratio for structures constructed or activities undertaken without a permit if the Department determines that mitigation, as defined in 25 Pa. Code Chapter 105.1, cannot be accomplished. B. Location/Siting Wetland replacement shall occur, where possible, immediately adjacent to the wetland affected by the obstruction or encroachment. If it is not practicable or feasible to locate the wetland replacement site adjacent to the impacted wetland, then every effort shall be made to locate the wetland replacement area along or adjacent to the watercourse which receives benefit from the impacted wetland system. If locating the replacement wetland adjacent to the watercourse is infeasible, then the site should be located within the watershed of that watercourse. In the event that no suitable sites can be found to meet the above criteria, the Department will then consider locating the replacement site adjacent to the next higher order stream (Strahler, 1964) or watercourse in the watershed. This procedure should be followed until an appropriate site is found. Only in extreme circumstances will the Department accept a wetland replacement proposal for construction in a watershed other than that where the loss has occurred. In the event that the wetland impact occurs within a designated Coastal Zone Management area (Lake Erie shore line, Delaware River - portions of Bucks, Philadelphia and Delaware Counties) then the wetland replacement must be undertaken in that Coastal Zone Management area. IV. Planning - Pre-Design Prior to initiating the design of the wetland replacement area, the following actions should be undertaken to determine existing conditions. A. Functional Assessment: Conduct a functional assessment of the wetland system to be impacted consistent with the criteria set forth in 25 Pa. Code Chapter 105.13(d)(2), and 105.13(d)(3). The functional assessment should be conducted according to an accepted methodology including WET 2.0 and/or HEP. The assessment should also include hydraulic and hydrologic analysis as necessary. For wetlands evaluated pursuant to 105.13(d)(2), the Department will accept an analysis based upon professional judgment, as long as that assessment is supported with appropriate documentation and justification. B. Impact Assessment: Evaluate the impact of the proposed project upon the functions identified in Subsection A above. C. Vegetative Analysis: Conduct a detailed survey of the vegetative community which currently exists in the wetlands. Include a discussion of diversity, density, distribution and stratification as it relates to function. 363-0300-001/February 11, 1997/Page 4
D. Hydrologic Analysis: Conduct a study to establish and define the regime and source of hydrology of the wetland system. Survey results should include data compiled through modeling or piezometric study; or supported professional judgment; whichever is most appropriate. V. Planning - Design The following steps are recommended to be followed in the design process: A. Establish goals: Establish a firm set of goals based upon the functions of the wetland to be impacted that will be achieved by the wetland replacement process. Estimate the replacement systems' functions, as defined in Chapter 105.1 and define criteria for determining success. B. Identify the preliminary replacement strategy: Determine what type of wetland system(s) must be replaced (i.e., emergent or scrub shrub or a combination thereof, seasonally saturated or saturated or inundated). Determine the necessary vegetative composition and interspersion of the various vegetative communities necessary to replace the habitat and functions to achieve the proposed goals. Determine the size of the replacement system necessary to guarantee replacement of lost functions. C. Select the replacement site: During the process of replacement site selection, consideration should be given to the following: (1) Conformance with the criteria in Section III-B (relating to Location/Siting). (2) Existing site conditions - conduct an evaluation of the existing site conditions to ensure that the site selected is not of such quality that its modification would result in a significant adverse impact. The Department would prefer that sites chosen for wetland replacement include sites with little or no current environmental values. (including, but not limited to fish and wildlife habitat, water quality or quantity parameters). (3) Evaluate the topography of the existing site. Is the topography of the site favorable for the construction of a replacement wetland? The chosen site should require minimal excavation or grading, and result in minimal waste material to accomplish necessary grades. (4) Will the site provide adequate hydrology? The Department prefers using groundwater for the primary hydrologic source, augmented with surface water (sheet flow), in wetland creation. The Department does not object to surface water augmentation but recommends against using surface water as a sole source, due primarily to the fact that it typically cannot be considered a dependable source of water. Since replacement wetlands are to be functional analogs and self perpetuating, the Department requires that hydrology be provided without the use of any mechanized or manual control devices 363-0300-001/February 11, 1997/Page 5
and recommends against constructed water control devices or any structures that would require human intervention or maintenance. (5) Situations to avoid. The Department recommends against utilizing the following areas for wetland replacement: (d) (e) (f) Wetlands of any size, type, age or origin. Mature forested systems. Areas which will require significant excavation or would result in extreme slopes to achieve necessary grades for wetlands establishment. Systems in which the hydrology sources are artificially controlled. Areas which would require the use of mechanized or manual water control devices. Sites of cultural, archaeological, historical or natural significance. D. Plan preparation: (1) Narrative: A narrative describing the wetland to be impacted, including an analysis of the functions of that wetland, and a narrative describing the functions of the proposed replacement wetland and how those functions approximate the wetland being replaced. (2) Hydrology: (d) (e) Depth: The location of water saturation and/or inundation above or below the soil surface (land/air interface). Energy: Changes in flow rates and velocities as they relate to erosion, flushing action and periodic inundations. Source: The source of the water saturation, such as groundwater, precipitation and surface water, over the various seasons of the year. Dependability ("Water budget"): Document the reliability of the hydrologic source(s) throughout the various seasons of the year (groundwater or surface water records). Quality: Analysis of water quality before and after the replacement activities. (parameters to be sampled include, but are not limited to: temperature, ph, turbidity, metals, organic compounds). 363-0300-001/February 11, 1997/Page 6
(f) Quantity: Base flow (discharge) at the outlet of the proposed wetland replacement site before and after replacement activities. (3) Construction Schedule: (Include anticipated dates if possible) (d) (e) Start date: Time frame for initiation of wetland replacement activities. Must be a date prior to or current with the anticipated date of construction of the permitted encroachment. Construction completion date: Time frame for completion of wetland replacement activities. Must be completed prior to completion of the permitted encroachment. Function date: Estimated date that the created wetland will be an independent functioning unit, providing the functions for which it was designed. Construction schedule: Schedule stating the estimated time frames and completion times for each phase of the wetland replacement activity. Planting schedule: Estimated dates for planting each of the proposed vegetative species. (4) Design details: (d) (e) (f) (g) Scale: Plans must be of a scale of 1:50 (one inch equals 50 feet) or larger (i.e., 1:30, 1:20, etc.). Plans must also include 1-foot or 2-foot contours. Elevation: Cross sections showing existing and proposed final site conditions. Grades: Show pre- and post-construction slopes of the ground. The postconstruction slope of the transition area between the replacement wetland and upland shall not be steeper than 5:1 (horizontal to vertical). Stockpile area: The location of stockpile areas, the type of material in each stockpile, and how long such piles will be utilized. Erosion and sedimentation control plan or permit. Staging area: Locations of all areas used to store machinery, equipment or supplies. Borrow areas: Source and location of any areas from which borrow material will be excavated. Non-coal surface mining permit may be required for certain activities. 363-0300-001/February 11, 1997/Page 7
(5) Substrate conditions: The organic (humic analysis) content of final (proposed) soil horizons. Texture of final (proposed) soil horizons. The nutrient composition of final (proposed) substrate. Discuss the nutrient content of any soil amendments, including any provision to control the release of those nutrients or amendments to downstream (outflowing) waters. (6) Vegetative conditions: Type: scientific and common name. Planting scheme. (i) (ii) (iii) (iv) Location: Within the plan, show the proposed location of each plant species. Density: The proposed density of each plant species in number per square meter, or some other accepted form of measure (eg. square foot, square yard, etc.). Diversity: A description of the diversity of the various sections within the proposed replacement wetland, and an analysis of the diversity of the entire wetland replacement site. Timing: Time of year each species will be planted to achieve maximum survival. (d) (e) (f) Proposed benefit to be derived by the use of each plant species: the function(s) of each of the plant species proposed. (i.e., a justification for the use of the proposed species). Proposed benefit derived from the aggregate vegetation: the interrelated functions of the plantings as a whole. Method of planting. Life stage of each plant species to be introduced, e.g., seeds, rhizomes, seedlings, mature plants, and commercial condition, (e.g., balled and burlaped, bare root, containerized, etc.). 363-0300-001/February 11, 1997/Page 8
(g) (h) (i) (j) (k) Anticipated survival rate of each plant species one year after planting. Anticipated percentage of ground cover of the species planted after one growing season. Listing of plants which have been selected for the replacement project that are adaptable to the natural substrate material without amendments to it. Description of the need for the infusion of amendments to the substrate, or lack thereof. Anticipated wetland conditions: the anticipated plant diversity and wetland functionality at the following intervals (i) (ii) One year after construction completion. Five years after construction completion. (l) (m) The source of all seed, plant stock and soil amendments. (Local seed source and plant stock preferable) Discussion of steps necessary to control wildlife damage. (7) Land use analysis: An analysis of any reasonably foreseeable land use change in surrounding areas that may impact on the proposed replacement wetland and a plan to mitigate potential negative land use impacts on the wetland. (Where feasible, preservation of a transition zone around replacement wetland) (8) Person responsible: The name, address and telephone number of the person or persons authorized and responsible to maintain and monitor the replacement wetland, to recommend or perform necessary changes and to correct impacts negatively affecting the replacement wetland. VI. Site Construction Unless otherwise authorized, construction of the wetland replacement system must occur prior to or concurrent with the permitted action which results in the impacts to the original wetland system. (Except for wetland replacement required as a remedy for a violation.) Prior to construction, it is imperative that an erosion and sedimentation control plan be developed for the replacement activities; the plan must be submitted to and approved by the Conservation District in the county in which work will occur prior to the commencement of activities. VII. Monitoring 363-0300-001/February 11, 1997/Page 9
The wetland replacement areas must be monitored for a period of not less than five years. The monitoring shall include periodic inspections by a qualified wetland specialist as many times as would be necessary, but at a minimum of twice a year for the first three years and once a year for the remaining two years. The inspections must occur during the growing season. The wetland specialist shall submit reports after each visit assessing the success of the wetland replacement activity. The report must include: a discussion of success to date, an analysis of the functions being provided, and discussions of any problems which have been or are being encountered. The report must also include photographs of the replacement site with a plan correlated to the location of each of the photos. At the end of two growing seasons, the wetland specialist shall conduct a detailed survey of the vegetative composition of the site. This survey must provide results of 100% coverage of revegetated areas, with at least 85% coverage by the hydrophytic species proposed in the replacement plan. If the 85% success has not been met, then additional planting must be undertaken to achieve that rate. The vegetational analysis must continue on a yearly basis until the 85% success rate is achieved. In those situations where wetland replacement is not successful, where the 85% survival criteria has not been met, or where the inspection reveals a problem; the post inspection report must include a discussion of remedial measures to correct the problems or deficiencies. In situations where alternative plants have colonized or invaded the site, the Department will evaluate the suitability of those species as it relates to maintaining the desired species in the replacement wetland, or undertaking steps to eliminate undesirable species. 363-0300-001/February 11, 1997/Page 10
VIII. General Notes A. The Department approved replacement plan must be implemented as approved and written. No modifications shall occur to that plan without written approval of the Department. If problems are encountered during the construction of the replacement site, which require modifications of the approved plan, the Department must be contacted to resolve those problems. B. In the event the replacement activities occur outside of the county and/or township in which the permitted encroachment or obstruction will be constructed; the permittee is responsible for notifying the county (if different) and township in which the replacement activities will occur of the proposed action. Proof of notification must be included as part of the replacement plan. Literature Cited Strahler, A.N. 1964. Part II. Quantitative Geomorphology of Drainage Basins and Channel Networks. pp 4:39-76. In: Handbook of Applied Hydrology. Ven Te Chow, Ed. New York: McGraw-Hill. 363-0300-001/February 11, 1997/Page 11