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HomeMy WebLinkAboutCAP 2007-04-24 Item 2B - Code Amendment - Sensitive Areas Ordinance (SAO) City of Tukwila Steven M. Mullet~ Mayor Department o/Community Development Steve Lancaster, Director INFORl\1ATION MEMO To: Mayor Mullet Community Affairs and Parks Committee t Jack Pace, Acting Director, Department of Community Developmen . April 19, 2007 Code Amendment - Sensitive Areas Ordinance From: Date: Subject: ISSUE Should the Sensitive Areas Ordinance (SAO) be amended to allow the mitigation ratios established in the SAG to be waived on a case-by-case basis if the mitigation is carried out at a wetland mitigation bank approved by other regulatory agencies and it is determined that the mitigation achieved meets the intent ofthe SAO? BACKGROUND Wetland mitigation banking as a tool for off setting unavoidable impacts to wetlands is increasingly becoming more important, and the City is starting to see proposals for off-site mitigation at banks. A wetland mitigation bank is the consolidation of small, fragmented wetland mitigation projects into a large contiguous site where creation, restoration and enhancement is carried out in advance of the impacts. Banks are established under a formal and rigorous permitting process. The City's current ordinance permits off-site mitigation, and even mitigation outside the city limits of Tukwila, as long as the mitigation site is within the same river basin. The mitigation ratios established in the SAG apply to both on-site and off-site mitigation. The SAG does not address transferring mitigation to a mitigation bank, which uses "credits" as opposed to acreage in determining the amount of mitigation needed. Determining if the amount of mitigation bank credits meet the City's mitigation ratios is not straightforward. Mitigation ratios applied to projects that are carrying out wetland mitigation in conjunction with a development project are typically higher than those ratios in a mitigation bank, because they factor in the element of risk that the wetland mitigation might fail. In wetland mitigation banks, however, the theory is that the wetland will already be mitigated well in advance of any development proposal - thus reducing the risk of mitigation failure (if the bank fails, credits cannot be released). Wetland mitigation banks typically take into CL Page 1 of3 04/1912007 9:33 :00 AM 0:\2007 SAO Amendment\CAP Memo.doc 6300 Southcenter Boulevard, Suite #100 · Tukwila, Washington 98188 · Phone: 206-431-3670 · Fax: 206-431-3665 Community Affairs and Parks Committee Proposed Code Amendment to Sensitive Areas Ordinance April 19, 2007 account the type of mitigation (restoration, creation, rehabilitation, enhancement) as our code does, but in addition, the credits are also based on the type ( class) of wetland that has been created, restored, etc. The City recently processed two land use applications submitted by the Washington State Department of Transportation (WSDOT) that provide examples of the problem presented by transferring wetland mitigation to a wetland mitigation bank. WSDOT sought approval to transfer mitigation for impacts to wetlands along Hwy 518 and 1-405 to the Springbrook Wetland Mitigation Bank, a mitigation bank area of over 125 acres located in Renton. The location ofthe highway construction on both Hwy 518 and 1-405 and the sensitive areas made it difficult to find room to adequately mitigate for wetland impacts in the remaining right-of-way. In addition, the size of the remaining sensitive areas available in the right-of-way would limit the effectiveness of any mitigation implemented. Thus off- site mitigation makes sense in these two cases. WSDOT proposed withdrawal of a certain number of credits from the bank as the proposed wetland mitigation. Credits in a mitigation bank are based on the net ecological benefit provided and are determined on the basis of Department of Ecology mitigation ratios, the kinds of mitigation carried out at the bank (wetland creation, restoration, and/or enhancement) and the total acreage for each type of mitigation. The number of credits needed for mitigation is based on the type (classification) ofthe wetland being impacted. The amount of mitigation built into the value of a credit does not directly equate to Tukwila's SAO mitigation ratios, which are based on acreage impacted and do not distinguish between types of wetlands in applying the mitigation ratios. This issue will arise again when applications are submitted for the Strander Blvd. extension, which will disturb Type 1 wetlands. The City of Renton will be requesting permission to carry out wetland mitigation in the Springbrook Wetland Mitigation Bank. WSDOT will also likely want to use the bank for future highway construction in Tukwila. Unless our SAO is amended to permit flexibility in the mitigation ratios, additional mitigation credits will be required to satisfy the SAO ratio requirements even though the net ecological benefits at the mitigation bank more than compensate for the wetland impacts. DISCUSSIONI ANAL YSISI AL TERNA TIVES The argument for carrying out the mitigation at a Mitigation Bank is that mitigation is completed in advance of impacts and generally results in improved hydrologic, water quality and habitat functions in a consolidated location. Studies of wetland mitigation banks have shown this to be true as long as the mitigation bank is maintained and monitored. CL Q:\2007 SAO Amendment\CAP Memo.doc Page 2 of3 04119/20079:33:00 AM Community Affairs and Parks Committee Proposed Code Amendment to Sensitive Areas Ordinance April 19, 2007 The mitigation bank established by the City of Renton and WSDOT was reviewed and approved by the State Department of Ecology, the u.S. Army Corps of Engineers, the Environmental Protection Agency, U.S. Fish and Wildlife Service, and the Federal Highway Administration and underwent rigorous review for compliance with both State and Federal requirements for wetland and stream protection and restoration. This review process is required for the establishment of any mitigation banle RECOMl\1ENDATION Staff proposes to amend the SAO as identified in the attached draft language to permit waiving, on a case by case basis, strict compliance with the mitigation ratios established in TMC 18.45 if off-site mitigation is proposed in a wetland mitigation bank that has been approved by the Department of Ecology, Corps of Engineers, EPA and other regulatory agencies and ifit is determined that the mitigation achieved meets the intent of the SAO. The next step would be to send this change to the Planning Commission for its review and a recommendation. Draft Amendment to TMC 18.45.090 Wetland Uses, Alterations and Mitigation Attachment A: CL Q:\2007 SAO Amendment\CAP Memo.doc Page 3 on 04119/20079:33:00 AM ATTACHMENT A PROPOSED AMENDMENT TO SENSITIVE AREAS ORDINANCE 18.45.090 Wetlands Uses, Alterations and Mitigation A. No use or development may occur in a Type 1, Type 2 or Type 3 wetland or its buffer except as specifically allowed by TMC Chapter 18.45. Any use or development allowed is subject to review and approval by the Director. Where required, a mitigation or enhancement plan must be developed and must comply with the standards of mitigation required in TMC Chapter 18.45. B. Alterations 1. Alterations to wetlands are discouraged and are limited to the minimum necessary for project feasibility. Requests for alterations must be accompanied by a mitigation plan, are subject to Director approval, and may be approved only if the following findings are made: a. The alteration will not adversely affect water quality; b. The alteration will not adversely affect fish, wildlife, or their habitat; c. The alteration will not have an adverse effect on drainage and/ or storm water detention capabilities; d. The alteration will not lead to unstable earth conditions or create an erosion hazard or contribute to scouring actions; e. The alteration will not be materially detrimental to any other property; and f. The alteration will not have adverse effects on any other sensitive areas. 2. Alterations are not permitted to Type 1 wetlands unless specifically exempted under the provisions of TMC Chapter 18.45. 3. Alterations to Type 2 wetlands are prohibited except where the location or configuration of the wetland provides practical difficulties that can be resolved by modifying up to .10 (one-tenth) of an acre of wetland. Mitigation for any alteration to a Type 2 wetland must be provided at a ratio of 1.5:1 for creation or restoration and 3:1 for enhancement and must be located contiguous to the altered wetland. 4. Isolated Type 3 wetlands may be altered or relocated only with the permission of the Director. A mitigation or enhancement plan must be developed and must comply with the standards of mitigation required in TMC Chapter 18.45. CL Q:\2007 SAO AmendmentiDraft Amendment.doc Page 1 of5 04!19i2007 9:30:00 Alv101!I&'2007 9:'19:00 :',;\'1 Attachment A Proposed Amendment to TMC 18.45.090 April 18, 2007 5. Mitigation plans shall be completed for any proposals for dredging, filling, alterations and relocation of wetland habitat allowed in TMC Chapter 18.45. 6. Isolated wetlands formed on fill material in highly disturbed environmental conditions and assessed as having low overall wetland functions may be altered and/ or relocated under TMC Chapter 18.45. These wetlands may include artificial hydrology or wetlands unintentionally created as the result of construction activities. The determination that a wetland is isolated is made through the Type 2 permit process. A mitigation or enhancement plan must be developed and must comply with the standards of mitigation required in TMC Chapter 18.45. C. Mitigation Sequencing. Applicants shall demonstrate that reasonable efforts have been examined with the intent to avoid and minimize impacts to wetlands and wetland buffers. When an alteration to a wetland or its required buffer is proposed, such alteration shall be avoided, minimized or compensated for in the following order of preference: 1. Avoidance of wetland and wetland buffer impacts, whether by finding another site or changing the location of the proposed activity on-site; 2. Minimizing wetland and wetland buffer impacts by limiting the degree of impact on site; 3. Mitigation actions that require compensation by replacing, enhancing, or substitution shall occur in the following order of preference: a. restoring wetlands on upland sites that were formerly wetlands; b. enhancing significantly degraded wetlands; c. creating wetlands on disturbed upland sites such as those with vegetative cover consisting primarily of exotic introduced species or noxious weeds. D. Mitigation Plans. 1. The mitigation plan shall be developed as part of a sensitive area study by a specialist approved by the Director. Wetland and/or buffer alteration or relocation may be allowed only when a mitigation plan clearly demonstrates that the changes would be an improvement of wetland and buffer quantitative and qualitative functions. The plan shall follow the performance standards of TMC Chapter 18.45 and show how water quality, wildlife and fish habitat, and general wetland quality would be improved. 2. In order to achieve the City's goal of no net loss of wetland functions and acreage, alteration of wetlands will require the applicant to provide a restoration or creation plan to compensate for the impacts to the wetland and will compensate at a ratio of 1.5 to 1. CL Q:\2007 SAO Amendment\Draft Amendment.doc Page 2 of5 04/]9/20079:30:00 AMO'I/I8.:2007 5:02:00 P\l Attachment A Proposed Amendment to TMC 18.45.090 Apri118, 2007 3. Impacts to wetlands may be mitigated by enhancement of existing significantly degraded wetlands, however, in order to achieve the City's goal of no net loss of wetland functions and acreage, mitigation through enhancement must be compensated at a ratio of 3:1. Applicants proposing to enhance wetlands must produce a sensitive area study that identifies how enhancement will increase the functions of the degraded wetland and how this increase will adequately mitigate for the loss of wetland area and function at the impact site. An enhancement proposal must also show whether existing wetland functions will be reduced by the enhancement actions. 4. The DCD Director may determine the number of wetland mitigation bank credits required to meet the the mitigation ratios established in this Chapter on a case by case basis through a Type 2 decision if: a) off-site mitigation is proposed in a Wetland ivIitigation Bank that has been approved bv the Deparhnent of Ecology, Corps of Engineers, EP A and other regulatory agencies; and b) it is determined that the lnitigation achieved through the number of credits proposed meets the intent of this Chapter. E. Mitigation Location. 1. On-site mitigation shall be provided, except where the applicant can demonstrate that: (a) On-site mitigation is not scientifically feasible due to problems with hydrology, soils, waves or other factors; or (b) Mitigation is not practical due to potentially adverse impact from surrounding land uses; or (c) Existing functional values created at the site of the proposed restoration are significantly greater than lost wetland functional values; or (d) That established regional goals for flood storage, flood conveyance, habitat or other wetland functions have been established and strongly justify location of mitigation at another site. 2. Off-site mitigation shall occur within the same watershed where the wetland loss occurred. 3. Mitigation sites located within the Tukwila city limits are preferred. However, the Director may approve mitigation sites outside the city upon finding that: (a) Adequate measures have been taken to ensure the non- development and long-term viability of the mitigation site; and (b) Adequate coordination with the other affected local jurisdiction has occurred. CL Q:\2007 SAO Amendment\Draft Amendment.doc Page 3 of 5 04/19/20079:30:00 AM01,'lK:2007 5:02:00 PM Attachment A Proposed Amendment to TMC 18.45.090 April 18, 2007 4. In selecting mitigation sites, applicants shall pursue siting in the following order of preference: (a) Upland sites that were formerly wetlands; (b) Idled upland sites generally having bare ground or vegetative cover consisting primarily of exotic introduced species, weeds or emergent vegetation; (c) Other disturbed upland; (d) Existing degraded wetland. F. Mitigation Standards. The scope and content of a mitigation plan shall be decided on a case-by-case basis. As the impacts to the sensitive area increase, the mitigation measures to offset these impacts will increase in number and complexity. The components of a complete wetlands mitigation plan are as follows: 1. Baseline information of quantitative data collection or a review and synthesis of existing data for both the project impact zone and the proposed mitigation site; 2. Environmental goals and objectives that describe the purposes of the mitigation measures. This should include a description of site-selection criteria, identification of target evaluation species and resource functions; 3. Performance standards of the specific criteria for fulfilling environmental goals, and for beginning remedial action or contingency measures. They may include water quality standards, species richness and diversity targets, habitat diversity indices, or other ecological, geological or hydrological criteria; 4. A detailed construction plan of the written specifications and descriptions of mitigation techniques. This plan should include the proposed construction sequence and construction management, and be accompanied by detailed site diagrams and blueprints that are an integral requirement of any development proposal; 5. Monitoring and/ or evaluation program that outlines the approach for assessing a completed project. An outline shall be included that spells out how the monitoring data will be evaluated by agencies that are tracking the mitigation project's progress; 6. Contingency plan identifying potential courses of action, and any corrective measures to be taken when monitoring or evaluation indicates project performance standards have not been met; and 7. Performance security or other assurance devices as described in TMC 18.45.210. CL Q:\2007 SAO Amendment\Draft Amendment.doc Page 4 of 5 04i19/2007 9:30:00/\,11,10'1/18:'200: :::0:::00 P~..l Attachment A Proposed Amendment to TMC 18.45.090 Apri118,2007 G. Mitigation Timing. Mitigation projects shall be completed prior to activities that will permanently disturb wetlands and either prior to or immediately after activities that will temporarily disturb wetlands. Construction of mitigation projects shall be timed to reduce impacts to existing wildlife, flora and water quality, and shall be completed prior to use or occupancy of the activity or development. The Director may allow activities that permanently disturb wetlands prior to implementation of the mitigation plan under the following circumstances: 1. To allow planting or re-vegetation to occur during optimal weather conditions; 2. To avoid disturbance during critical wildlife periods; or 3. To account for unique site constraints that dictate construction timing or phasing. H. Permitted Uses Subject to Exception Approval. Other uses may be permitted upon receiving a reasonable use exception pursuant to TMC 18.45.180. A use permitted through a reasonable use exception shall conform to the procedures of TMC Chapter 18.45 and be consistent with the underlying zoning. CL Q:\2007 SAD Amendment\Draft Amendment.doc Page 5 of5 04119/20079:30:00 /\.M01.'18.'200: 5:0~:OO P~..!