Hillside Terrain
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● Soil & Wetland Studies ● Ecology ● Application Reviews ● Listed Species Surveys ● GPS ● Environmental Planning & Management ● Ecological Restoration & Habitat Mitigation ● Expert Testimony ● Permitting January 20, 2021 Town of Farmington Town Plan & Zoning Commission 1 Monteith Drive Farmington CT 06032 RE: Preliminary Review “Proposed Zone Change & Residential Development” 402 Farmington Ave and Quarry Rd REMA Job #21-2357-FAR48 Dear Chair Brenneman & Commissioners: Rema Ecological Services, LLC (REMA), has been engaged to review the development proposal, principally for the Conservation/Inland Wetlands Commission, but there are also important implications for the planning and zoning commission, from a general ecological perspective that we would like to address. We should note that we have read Dr. Michael Klemens’ Report to your commission, dated January 17, 2021, and concur with all the points in his analysis, and we have reviewed the Milone & McBroom, Inc. (MMI) Wetland Delineation and Impacts Assessment, dated November 2nd, with an accompanying plan set. In several regards, it is our professional opinion that the proposed development project is not consistent with the Farmington Plan of Conservation & Development (POCD, updated 2007, adopted 2008) and the 2018 Addendum. Hillside Terrain Section V1 of the POCD, entitled Hillsides/Ridgelines, on p. 22 and 23 describes the four types of geologic formations found in the town, that result in hilly terrain, including the Rema Ecological Services, LLC ● 164 East Center Street, Suite 2, Manchester, CT 06040 ● 860.649-REMA (7362) ● 860.647.8397 (fax) Farmington Town Plan & Zoning Commission RE: Proposed Residential Development, 402 Farmington Av. & Quarry Rd. January 20, 2021 Page 2 eastern traprock ridge system along Talcott Mountain. The geologic processes that formed the conspicuous Metacomet (traprock) Ridge are explained therein. As Dr. Klemens points out, the Planning Objectives part of this Section (p.24) recommends in Section 1: “low density residential use of hillside areas” to preserve the aesthetic and environmental values of forested hillsides, and, in Section 2: “Encourage residential development which minimizes the disruption of groundcover and vegetation and which preserves expanses of open space in order to preserve the aesthetic and natural functions of hillsides and ridgelines.” The proposed project will include 1.54 acres of tree clearing within the upland review area to wetlands and watercourses. The total amount of soil/forest disturbance is not part of the applicant’s Impact Assessment Report. Based on the Connecticut Web Soil Survey, the building site has variable topography; mapped as Unit 87C, 8-15% slopes, Wethersfield Loam and Unit 77C (Holyoke/Cheshire complex (3-15%). As soil scientists we note that B horizons of Wethersfield loam and the Holyoke series are fine textured and highly erosible, with an erosion “K” factor of 0.43; this increases erosion risk on moderate slopes. Ecological connectivity is another value encouraged by low density residential zoning, a point also emphasized Dr. Klemens; this benefit also applies to plants, insects, and avians. If natural habitat areas in a low-density residential zone are large enough to produce a surplus of seeds or offspring, they can disperse to other habitat areas – the “stepping stone” mode type of connectivity, which supplements movement through continuous core habitat, for many species. Quoting from Section V1 of the POCD: “Farmington has long recognized the aesthetic and environmental values of hillside areas. The low-density residential development, which characterizes most of these areas has maintained the visual character of hillsides in addition to limiting erosion and reducing flood hazards in adjacent low-lying areas. Hillside development requires careful planning for the following reasons: - Substantial destruction of vegetation can result in increased runoff and sedimentation requiring increased public expenditures for flood control and storm water management. Farmington Town Plan & Zoning Commission RE: Proposed Residential Development, 402 Farmington Av. & Quarry Rd. January 20, 2021 Page 3 - Certain hillsides contribute to the natural beauty of the surrounding area. This beauty depends, to a large extent, on the existence of significant amounts of open space and on development, which is in keeping with the surroundings, and natural constraints of the land. Low-density zoning, the land's natural constraints and the lack of public sewers have all helped to maintain the aesthetic values and natural functions of these areas. Conditions attached to subdivision approvals have also been used to control erosion and to preserve vegetation on hillsides. The existing upgradient, large-lot residential subdivision, e.g. along Prattling Pond Road, was consistent with this section of the POCD. It did not involve cuts and fills on a significant proportion of the forested hillside. It has left a high proportion of undisturbed forest soil and leaf litter, habitat for plants, invertebrates, and upland habitat for amphibians. It also left multiple wide interconnected swaths of forest cover with natural duff, leaf litter, and forest floor invertebrates – and plants – that continue to provide habitat connectivity for wildlife including spotted turtles and salamanders. The existing highly decentralized stormwater management is much less disruptive to downgradient soil function, fertility, and hydrology than the proposed, large, centralized stormwater facility. Upgradient of the proposed construction site, in the low-density residential zone, infiltrated precipitation continues to move slowly downslope. Continuous groundwater seepage weathers minerals from the parent rock materials in the subsoil, enriching and moistening the soil on the lower slope of any hillside, but especially on a traprock ridge. Like Dr. Klemens, we draw the attention of the Zoning Commission to the Planning Objectives portion of Section VIII of the POCD (Future Land Use Plan). Section 3, calls for that very high-density residential development (over 5 units/acre) to occur only where slopes are <10%. Section 2, reiterates the widespread zoning principle, calling for new development that is compatible with existing development, with regard to density, etc. Traprock Ecosystem The ecological community under review is the eastern slope of a traprock ridge, which substantially raises the bar for impacts assessment. Section IX of the POCD, entitled Flora & Fauna, begins on p. 44 and 45 with a discussion of the four critical habitats found in Farmington Town Plan & Zoning Commission RE: Proposed Residential Development, 402 Farmington Av. & Quarry Rd. January 20, 2021 Page 4 Farmington, beginning with the traprock ridge found in Eastern Farmington, Talcott Mountain. As Dr. Klemens also points out, traprock ecosystems have unusually high biodiversity, especially for wildflowers, as documented by the Farmington Biodiversity study. A 1976 CTDEEP publication by Dowhan & Craig “Rare and Endangered Species of Connecticut and their Habitats” is cited, pointing out: “the importance of "critical" or rare habitats in the preservation of rare and endangered plant and animal species. Many species are rare or endangered because suitable habitats for their survival exist in only a few areas. Since these isolated habitats are critical to the survival of many of Connecticut's rare and endangered species, they are termed critical habitats.” In his reports to the Town of Farmington, herpetologist Dr. Klemens noted that a high proportion of rare herptile species in the Talcott Ridge traprock ecosystem: five Connecticut-listed reptiles and amphibians that use both upland and wetland habitats on the ridge. The current low density residential zoning allows seasonal movements between wetlands on the upper portion of the mountain, and the wetlands along the eastern base of the ridge, just downgradient of the proposed project. The references section of this report includes more recent publications on critical habitats and traprock ridge ecology. Dr. Klemens emphasized the inadequacy of the applicant’s field vernal pool surveys, in several regards. The attached list of rare and uncommon plant species found in traprock habitats underscores the need for a thorough botanical survey during the growing season, from early Spring to early Fall. No such survey has been completed. Not even widespread traprock dominant species like maple leaf viburnum are mentioned in this application, and the proposed planting plan has little in common with a natural traprock plant community. REMA has found significant, sensitive botanical resources at almost every large traprock site we have evaluated, over three plus decades. Seed collection and transplanting can help salvage such a find, but first a robust floristic inventory is needed! To briefly explain the scientific basis for the high biodiversity in traprock ecosystems: Forest vegetation is also significantly more diverse on hillside sites, such as traprock or marble ridges, where the bedrock/ glacial debris weathers into sub-acidic, mineral-rich soil. These hillsides support robust populations of many plant species, that are uncommon or absent in typical forest with more acidic soil. Hop hornbeam (Ostrya virginiana) and spoon-shaped groundsel (Packera obovata) are two examples. Both these plants are common on traprock-derived soils. They are too sparse on the typical acidic soils found in Farmington Town Plan & Zoning Commission