Environmental Inventory and Analysis: 1.7Geology, Soils, and Topography
A soil survey map of the town is available from the Soil Conservation Service Middlesex Conservation District. The soil mapping delineates the various soil types throughout the town. A description of each soil type including the suitability of the soils for many land uses is also furnished by the Soil Survey Report ("Middlesex County - Massachusetts - Interim Soil Survey Report, Second Edition, July 1986 by Middlesex Conservation District").
Based on the soil characteristics, the degree of limitation to building site development is classified as low, moderate or high. Low limitations indicate the soil's properties are favorable for development and any limitation is minor and easily overcome. Typically, the low limitation soil group is moderate to well drained gravely and sandy materials with suitable depth to the ground water table with low to moderate slope.
Moderate limitations indicate soil properties and site features unfavorable for development, but the limitations can be overcome or minimized by special planning and design. The moderate limitations soil group consists of a mix of soil types such as silt/clay, organics, rocks and sand/gravel. Moderate limitations can be caused by wetness due to limited depth to ground water, moderate to significant slopes creating erosion hazards, rocky conditions increasing difficulty for excavation, organic and clay/silt materials limiting foundation support capacity.
Severe limitations indicate soil properties or site features so unfavorable or difficult to overcome that a major increase in construction effort, special design, or intensive maintenance is required. This soil group includes areas with substantial amounts of rock or ledge, year-round high ground water table, severe slopes (15 - >25%), or unstable materials with little bearing capacity.
Figure 4-1 presents an overlay of the three soil types grouped by development limitations. The predominant soil type group is moderate development limitations. The low limitations and severe limitations soil groups, which make up the remainder, are about equally divided.
In relation to the remaining unprotected open space in town, the large tracts of land containing soil groups of low and moderate development limitations include McLean Hospital, Belmont Country Club, Audubon Land, Belmont Hill School, and the O’Neill Property (formerly owned by Arthur D. Little). Of the preceding, the McLean Hospital and the O’Neill private property parcels would be the most likely to see future development on a large scale without acquisition of the open space or implementation of conservation restrictions.
Figure 4-1 - Map of Belmont's Soil Types Grouped by Development Limitations
1.7.2topography
Two predominant geologic features dominate the topography of Belmont; Wellington Hill located north and west of Pleasant Street, and Meetinghouse Hill located in Watertown, immediately south and adjacent to Belmont Street. Wellington Hill rises to an El. 288 ft opposite Somerset St. with a steeply south facing rock outcrop slope between Belmont Center and Waverley Square. Meetinghouse Hill is more gently sloping on its northern flank, the portion in Belmont that defines the topography between Fresh Pond to the east and Waverley Square to the west. The highest elevation in this area is approximately El. 164 ft with grades slopping downward to El. 49 ft to the east, north and west. The relatively flat Winnbrook lowlands area (El. 10 ft to El. 33 ft) is located east of Pleasant Street and north of Concord Avenue. Elevations are referenced to mean low water datum and are stated in feet.
1.7.3overburden soils
The land area of Belmont as indicated by the topography is dominated by two distinct hills that consist of shallow bedrock overlain by glacial till, an unsorted mixture of silt, sand and clay with numerous boulders and cobbles. The Winnbrook area located north and east of the bedrock controlled hills of Belmont is underlain by a thick deposit (80 to 100 ft.) of marine clay and sand. In the past, the clay was mined to make bricks at the Parry Brick Yard, producing up to 300,000 bricks per week. The remnants of this brick manufacturing are Clay Pit Pond located on Concord Avenue in front of the High School. Much of the land area of the Town was previously used for agricultural purposes, having loam topsoil.
1.7.4development and recreation opportunities
As discussed earlier in this section and illustrated in map form (Figure 4-1), land within the Town is typically suitable for development of either residential or recreational facilities with the principal exception of the steeply sloping area along the south face of Wellington Hill. Development of playing fields will generally require earthwork to create level areas for fields. Excavations within hill portions of the Town may encounter shallow bedrock or numerous boulders or cobbles in the near surface soils.
1.8Landscape Characteristics
Belmont's most notable expansive vistas are from the McLean Hospital property looking generally westward over the protected open spaces of Rock Meadow and the Met State Hospital lands. This rural vista typifies historic Belmont as shown in a painting by Winslow Homer, "Boys in a Pasture" depicting two young farm boys in a field adjacent to the current Audubon Highland Farms property.5 Efforts to preserve Rock Meadow and the McLean Hospital lands in a rural character date back to the last century.
The larger Belmont Hill landform, of which the McLean lands are part, are in the north-central to north-western area of town. They provide the only sizable relief in an otherwise quite level and unremarkable terrain.
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