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HomeMy WebLinkAboutLog133 MEMORANDUM TO: Stacie Hoskins FROM: Donna Frostholm DATE: August 31, 2006 RE: Discovery Bay Golf Club PRRD The following are my comments and recommendations for the Discovery Bay Golf Club PRRD, and are based on my review of submitted materials as they pertain to wetlands. Review Comments 1. The April 21, 2005 Wetland Delineation Report (Log Item 22) states that the west boundary of Wetland A, which is a Category I wetland, was not delineated and that the wetland in this area was mapped based on a previous wetland delineation conducted in 1996. The report states that the west wetland boundary will be delineated prior to construction. The entire wetland must be delineated prior to preparing a mitigation plan so that the extent of wetland buffer on the property can be accurately determined and all potential impacts to wetland buffers can be addressed in the mitigation plan. The County should be notified once the wetland delineation is complete so the delineation can be verified. 2. The drawings submitted by the applicant have the wetland label and wetland category reversed for Wetlands Band C. Wetlands should be identified on all submitted drawings such that they match the wetlands as described in the April 21, 2005 Wetland Delineation Report (Log Item 22) and as shown on a figure in a previous Wetland Delineation Report, which is dated June 4,2006 (Log Item 62). 3. Based on the description of Wetland B in the Wetland Delineation Report (Log Item 22), I disagree that this wetland is a Category IV wetland. For a wetland to be considered a Category IV wetland, it must be dominated by one class of vegetation (among other things); however, the wetland report describes the wetland as having two wetland classes. For this reason, it appears that Wetland B should be a Category III wetland, which requires a 50-foot buffer. In reviewing the plan sheets submitted by the applicant, it appears that the proposed development would be located beyond the 50-foot buffer. 4. Wetland A and the associated stream continue north ofthe property boundary. The wetland and stream need to be delineated and impacts avoided to the extent possible during construction of the Larry Scott Trail (LST). It is my understanding that the proposed trail will use existing easements along the north and east sides of the property. Any unavoidable impacts to the wetland, stream, or buffer must be addressed in the mitigation plan to be prepared for the project. 5. The preliminary mitigation concept, as described in the January 19, 2006 letter from the applicant's wetland biologist (Log Item 72), is generally acceptable, and a detailed mitigation plan must be prepared for County review and approval. The mitigation plan should address all LOG ITEM # . -___L"53 Page._LOf~ potential impacts to environmentally sensitive areas and buffers, including but not limited to, those associated with construction of Hutson Road, installation of utility lines, clearing for gravel access roads, and construction of the LST. Any portion of the Wetland A buffer that will be maintained for use in golfing post-construction (i.e., those areas that cannot be enhanced with native plant species) cannot be considered buffer enhancement area. 6. Surface water runoff from the area to be developed as The Meadows contributes water to Wetland A. Construction of Hutson Road will likely block or intercept surface water runoff to the wetland. Limiting the amount of water to the wetland has the potential to make the on-site portion of the wetland drier. For this reason, the applicant must maintain drainage patterns to the wetland post-construction and the plan sheets should show how water from the upland areas will be conveyed to the wetland. Any alteration of wetland hydrology needs to be addressed in the mitigation plan. 7. The easement for the water line that parallels Hutson Road is shown on the plan sheets. However, the location of the utility line easement to the areas of residential development is not shown on the sheets. These should be shown on the plan sheets (for example, if the Wetland A, the stream, or the buffer must be crossed to provide utilities to The Lily Pond, this must be shown on the drawings and appropriate mitigation provided). 8. Work areas, including areas where soils will be stockpiled, are not identified on the plan sheets. Work areas must be located outside of wetland buffers. 9. The applicant should clarify if any improvements to the golf course will be conducted within the wetland buffers. It is not obvious from the plan sheets if improvements are proposed. 10. If any earthwork is conducted prior to approval of the mitigation plan, sediment and erosion control measures must be provided around the wetland buffer, per buffer widths in Table 3-3 (JCC 18.15.340). Recommendations Based on my review, I recommend the following be included in the staff report as conditions of approval: 1. Wetland boundaries along the north and west side of Wetland A must be delineated prior to preparing the mitigation plan so all potential impacts to the wetland, stream, and buffers can be evaluated in the mitigation plan. 2. Information submitted by the applicant must identify the wetland category for all wetlands on the plat and plat drawings must show the buffers for each wetland identified. 3. All drawings submitted by the applicant should be labeled as shown in the Wetland Report prepared for the project, and Wetland B should be identified as a Category III wetland with a 50- foot buffer. 4. Utility line easement to the residential development must be located outside of wetlands, streams, and buffers to the extent possible. For any unavoidable impacts to sensitive areas and associated buffers, mitigation must be provided and described in the Mitigation Plan. 5. Construction of roads cannot adversely affect the quantity and timing of water flowing from the uplands (e.g., The Meadows) to the wetlands. Drainage patterns to the wetlands post- LOG ITEM # . {3~ Page -,_.~_.._9t.3_-_, construction must be maintained and plan sheets must show how water from the upland areas will be conveyed to the wetlands. 6. The Mitigation Plan prepared for the project must address the direct impacts to Wetland A, the stream, and the buffer. Direct impacts could include, but are not limited to, construction of Hutson Road, installation of utility lines, clearing for gravel access roads, construction of the LST, and golf course improvements. The mitigation plan must also address any potential impacts to wetland hydrology from construction of Hutson Road. 7. Any areas within the buffer of Wetland A that will be maintained for golfing use post- construction cannot be considered buffer enhancement areas. Only those areas that can be planted with native plant species can be considered buffer enhancement areas. 8. All work areas, including stockpiling of soils, must be located outside of wetland buffers. 9. To protect the wetlands and the stream, sediment and erosion control measures must be installed before beginning any earthwork. For any ground disturbing activities to be conducted as part of plat development prior to County approval of the mitigation plan, sediment and erosion control measures (e.g., siltation fencing, straw bales) must be installed 225 feet from the edge of the Category I wetland and 75 feet from the edge of the Category III wetlands. l()G ITEM ,.#---_ I S ~ ;-JapE' 3 "'f:3 " .... v - ~._, -" ."-"" .,.....,"" -.