3. Soils Overview



3.1 Introduction

This section provides a description of the soil associations found within the Central Pine Barrens area and includes a discussion of critical soil resources. This section was based on the Suffolk County Soil Survey prepared in 1975 by the United States Department of Agriculture Soil Conservation Service in cooperation with the Cornell Agricultural Experiment Station.

A soil association is a group of soils geographically associated in a characteristic repeating pattern. Associations allow the comparison of large tracts of land as to their suitability for certain kinds of land use and provide guidance for the management of large tracts such as watershed or wildlife areas. It is not suitable to use these general soils associations for specific parcel comparisons, since soils in any one association often differ in slope, depth, stoniness, drainage and other characteristics.

Information on the limitations of specific soil types within an association for certain uses are indicated in Appendix 1-1. The limitations of a soil for a certain use is due to it having a property not conducive for that use. For instance, areas that have soils with a high water table would not be suitable for cesspools.

Soil resources within the Central Pine Barrens area include prime agricultural soils that have already been cleared and soils with a high water table that are indicative of environmentally sensitive areas such as wetlands and tidal marshes.
 

3.2 Description of General Soils Associations

Four soil associations are located within the Central Pine Barrens area as identified from the general soils map in the Soil Survey. (Soil Survey 1975). These are shown on Figure 3-1 and are identified as: 2 - Haven-Riverhead Association; 3 - Plymouth-Carver Association, Rolling and Hilly; 4 - Riverhead-Plymouth-Carver Association; and 10 - Plymouth-Carver Association, Nearly Level and Undulating.

3.2.1 Haven-Riverhead Association

The Haven-Riverhead Association is located as a band varying in width from 2 to 4 miles wide along the northern portion of the Central Pine Barrens area (see Figure 3-1). According to the Soil Survey, this association consists of deep, nearly level to gently sloping, well-drained, medium-textured and moderately coarse textured soils on outwash plains. Characteristically it is nearly level with short gentle slopes along shallow drainageways with some areas pitted by steep-sided kettle holes. Slopes range from 1 to 12 percent in this association.

The Soil Survey states that this association constitutes 26 percent of the county soils and is comprised of approximately 40 percent Haven soils and approximately 30 percent Riverhead soils, with the remaining 30 percent of this association consisting of minor soils. This association constitutes approximately 25 percent of the Central Pine Barrens area. The Haven and Riverhead soils are found together across most landforms. However, Haven soils are most extensive at slightly higher elevations and at greater distances from drainageways.

Figure 3-1: General Soil Map, Suffolk County, New York
(Please see the printed version of the Plan for this illustration.)

The Soil Survey describes Haven soils as deep, well drained and medium textured soils, whereas Riverhead soils are described as deep, well drained and moderately coarse textured soils. The surface layer of Haven soils is loam and their subsoil is loam or silt loam. The surface layer and subsoil of Riverhead soils is sandy loam. Both Haven and Riverhead soils are present throughout the county with Haven soils mostly found on outwash plains located between the two terminal moraines. Riverhead soils are found on rolling to steep areas on the moraines and in level to gently sloping areas on outwash plains. Slopes for Haven soils can range from 0 to 12 percent, but generally range from 1 to 6 percent. Slopes for Riverhead soils are characterized as nearly level to steep, however they are generally nearly level to gently sloping. The substratum for both Haven and Riverhead soils is sand and gravel. The depth to the substratum for Haven soils ranges from 18 to 36 inches and 22 to 36 inches in Riverhead soils.

Minor soils of this association, as stated in the Soil Survey, include steeper Carver and Plymouth soils that are found on the sides of drainageways and on the steep sides of kettle holes. Soils of the Haven series' thick surface layer are found in the bottom of shallow depressions. Soils within this association that have a high water table include Canadice (Canadice soils are in low-lying wet areas west of the Village of Greenport), Raynham, Scio, and Sudbury soils. Raynham, Scio, and Sudbury soils are found in low-lying areas near ponds or marshes. The largest such area is near Brookhaven Laboratory.

According to the Soil Survey, native vegetation for the Haven-Riverhead association consists of black oak, white oak, red oak, and scrub oak. Native vegetation for the Haven soils is the pitch pine vegetation. The majority of the areas within this association have been cleared. The soils of this association from the Brookhaven-Riverhead town line eastward comprise the largest area of farmland in the county. These lands are used extensively to grow potatoes and other vegetables. These soils are predominantly gently sloping to nearly level and have moderate to high available moisture capacities. Crops within these soils respond well to applications of lime and fertilizer. These factors make this association one of the best farming areas in the county. Appendix 1-1 presents the limitations of soils within this association for particular uses related to planning. Since these soils have good drainage and can be excavated with ease, the Soil Survey considers this association to have an excellent potential for housing developments and similar uses, except in areas with a higher water table or that are strongly sloping which would place more severe limits on non-farm uses.

3.2.2 Plymouth-Carver Association, Rolling and Hilly

The Plymouth-Carver Association, rolling and hilly is located in a central band varying in width from one to two miles wide from the western boundary of the Central Pine Barrens area and widening to 4-5 miles wide east of Yaphank to Riverhead (see Figure 3-1). This association is described in the Soil Survey as consisting of deep, excessively drained, coarse-textured soils that are located on the Ronkonkoma moraine. The soils within this association are characterized as strongly sloping to steep with slopes ranging from 8 to 35 percent.

The Soil Survey states this association constitutes 19 percent of the county soils. It is comprised of approximately 45 percent Plymouth loamy sand soils and approximately 30 percent Carver and Plymouth sands with the remaining 25 percent comprised of minor soils. This association constitutes 50 percent of the Central Pine Barrens area. Plymouth and Carver soils are deep and excessively drained. Plymouth soils have a surface layer and subsoil of sand or loamy sand. Carver soils have a surface layer and subsoil of sand and are similar to Plymouth soils, except they have a distinctive gray or light-gray subsurface layer that is lacking in Plymouth soils. Both Plymouth and Carver soils have a substratum of sand and gravel. The depth to the substratum in Plymouth soils ranges from 20 to 36 inches and in Carver soils, 16 to 32 inches.

Carver and Plymouth sands are generally found on steeper soils on ridgetops and the lower part of slopes. Gently sloping Plymouth loamy sand soils are mainly on the intervening areas. Areas along the crests of some ridges have a large amount of gravel on the surface that are generally small and scattered throughout the association.

Minor soils in this association include Haven and Riverhead soils that are nearly level and scattered throughout this association; Atsion and Berryland soils along with the land type identified as Muck have a high water table and are situated adjacent to streams, ponds and marshes. The largest areas of these soils and land type are along the Peconic River and nearby ponds, with these areas extending eastward from the headwaters of the river to its mouth in Riverhead. There is extensive cut and fill land in the western portion of this association.

According to the Soil Survey, the soils of this association have a characteristically poor cover of scrub oak, white oak, black oak and pitch pine. Additionally, only a small portion of this association has ever been farmed. This association provides an important source of gravel in the County. Appendix 1-1 presents the limitations of soils within this association for particular uses. In the western portion of the county, this association is largely in housing developments. It is considered by the Soil Survey to be poorly to fairly suited for crops commonly grown in the county. Furthermore, steep slopes on much of the area and difficulty in establishing and maintaining lawns and landscape plantings severely limit the use of these soils for housing developments or similar nonfarm uses. Severely limiting the use of some areas for sewage effluent disposal are the areas of soils within this association that have a high water table. There are soils within this association with a rapid permeability that would allow water and wastes to move quickly from cesspools and septic systems and potentially cause contamination of groundwater supplies (see Appendix 1-1).

3.2.3 Riverhead-Plymouth-Carver Association

The Riverhead-Plymouth-Carver Association extends in a west to east band ranging from less than .5 miles to 2 miles in width along the southern portion of the Central Pine Barrens area boundary. This association is described in the Soil Survey as deep; nearly level to gently sloping; well-drained and excessively drained; moderately coarse textured and coarse textured soils on the southern outwash plain. Slopes range from 1 to 6 percent with slopes that range from 8 to 35 percent on the sides of drainage channels. The portion of this association that adjoins the Great South Bay and Moriches Bay along its southern edge is indented by many short tidal creeks.

According to the Soil Survey, this association constitutes 21 percent of the county soils. This association is comprised of approximately 45 percent Riverhead soils, approximately 30 percent Plymouth loamy sand soils and approximately 10 percent Carver and Plymouth sands with the remaining 15 percent of this association comprised of minor soils. This association constitutes approximately 10 percent of the Central Pine Barrens area. Riverhead soils are deep and well drained, whereas Plymouth and Carver soils are deep and excessively drained. Riverhead soils have a surface layer and subsoil of sandy loam with many areas of the lower part of the subsoil being loamy sand. Plymouth soils have a surface layer and subsoil of loamy sand or sand. Carver soils have a surface layer and subsoil of sand. The substratum of all three soil series are sand and gravel. The depth to substratum in Riverhead soils is 22 to 36 inches, in Plymouth soils, 20 to 36 inches and in Carver soils 16 to 36 inches.

The nearly level Riverhead and Plymouth soils are dominant on broad, flat areas between intermittent drainageways with Riverhead soils at slightly higher elevations and greater distances from the drainageways than the Plymouth soils. Carver soils are located on the sides of intermittent drainageways.

Minor soils within this association include Haven soils that are adjacent to Riverhead soils but at slightly higher elevations. Other minor soils within this association include Berryland, Walpole and Wareham soils and the land type Tidal marsh that have a high water table. These later soil types and land type are found along the margins of tidal creeks or at the southern ends of drainageways that have elevations near that of the water table. Large areas of Riverhead and Haven soils have been altered by grading operations in developed areas. There are also large areas of cut and fill in this association where housing tracts have been developed. The Soil Survey indicates the native vegetation within the Riverhead soils areas of this association consists of black oak, white oak, red oak, and scrub oak. Within the Carver and Plymouth soils it consists of scrub oak, white oak, black oak, and pitch pine.

This association is largely in woods within the inland area of the Central Pine Barrens. According to the Soil Survey, areas that are primarily developed are located along the shore with development gradually encroaching into the inland areas. Appendix 1-1 presents the limitations of soils within this association for particular uses related to planning. Due to the coarse-texture of the Plymouth and Carver soils, the suitability of the soils of this association for farming are limited. However the areas of Riverhead soils are suited for most locally grown crops. This association is well suited to urban and suburban development due to its level topography, ease of excavation and good drainage. Effluent from cesspools and septic systems that are located in soils with high water tables could potentially contribute to groundwater contamination. Wet soils within this association are severely limited for most nonfarm uses.

3.2.4 Plymouth-Carver Association, Nearly Level and Undulating

This association is found only in two areas within Suffolk County which are also located within the Central Pine Barrens area. One is in the vicinity of Coram and the other covers a broad sandy plain that extends eastward from Eastport to Hampton Bays (see Figure 3-1). The only breaks in these flat areas occur from widely spaced drainageways. This association is described in the Soil Survey as deep, excessively drained, coarse-textured soils on outwash plains and is characteristically nearly level. The western part of this association consists of more strongly sloping soils than the eastern part. The eastern area was laid down by glacial outwash and is not pitted. Slopes within this association generally range from 1 to 8 percent with a few areas that are steeper.

The Soil Survey states this association constitutes 5 percent of the County. This association is comprised of approximately 50 percent Plymouth loamy sands and approximately 25 percent Carver and Plymouth sands with the remaining 25 percent comprised of minor soils. This association constitutes approximately 15 percent of the Central Pine Barrens area. Plymouth and Carver soils are deep and excessively drained. Plymouth soils have a surface layer and subsoil of sand or loamy sand. Carver soils have a surface layer and subsoil of sand and are similar to Plymouth soils, except they have a distinctive gray or light-gray subsurface layer that is lacking in Plymouth soils. Both Plymouth and Carver soils have a substratum of sand and gravel. The depth to the substratum in Plymouth soils ranges from 20 to 36 inches and in Carver soils, 16 to 32 inches.

The Soil Survey identifies Haven, Riverhead, Atsion, Berryland and Wareham soils as minor soils within this association. There is extensive cut and fill land in the western part of this association. Riverhead and Haven soils are well drained while Atsion, Berryland and Wareham soils are more poorly drained. The western part of this association has been used mainly for housing and developments. The eastern part of this association is wooded except for the airfield area at Westhampton Beach.

According to the Soil Survey, native vegetation for this association is characterized by a poor cover of scrub oak, pitch pine, and white oak. It is not well suited for most crops grown in the County due to its course texture, droughtiness and low fertility. Notwithstanding their coarse texture, these soils have few limitations for nonfarm uses. (See Appendix 1-1). Due to the droughty nature of soils within this association, it has severe limitations for use in establishing and maintaining lawns and foundation plantings. Cesspools and septic systems located within rapidly permeable soils in this soil association could potentially contribute to the contamination of water supplies beneath them. Minor soils with a high water table have severe limitations for nonfarm use.
 

3.3 Soil Resources Associated with Environmentally Significant Resources

Soil resources within the Central Pine Barrens area include prime agricultural soils on previously cleared land and soils and land types that have a high water table and are associated with environmentally sensitive wetland and tidal marsh areas.

3.3.1 Prime Agricultural Soils

Soil capability groups, as defined in the Soil Survey, were used to identify prime agricultural soils within the Central Pine Barrens area. Prime agricultural soils within the Central Pine Barrens area are identified on the Prime Agricultural Soils Map included in Appendix 1-2. These soils are within capability classes I and II since they have few or moderate limitations that reduce the choice of plants or require moderate conservation practices. Included in these soil classes are:


3.3.2 Soils Associated with Environmentally Sensitive Areas

Atsion, Berryland, Canadice silt loam, Muck, Raynham, Scio, Sudbury, Walpole, Wareham, and Tidal marsh soils and land types are soil resources associated with environmentally sensitive wetland and tidal marsh areas. These soil and land types have characteristically high water tables that are indicative of wetland and tidal marsh areas. The discussion of associations that contain these soils can be found at the beginning of this section. These soils are generally found in low lying areas near streams, drainageways, ponds or marshes. Soils such as these with high water tables could potentially contribute to groundwater contamination from effluent from cesspools and septic tanks and have certain severe use limitations as indicated in Appendix 1-1.