The topographic characteristics of the Township are mostly undulating with a few dramatic, steep slopes along the Swimming River Reservoir and the system of streams feeding into it. The topographic characteristics illustrate a clear cut, dominant drainage pattern flowing to the east as shown on Plate 2, Topography. The lowest elevation is just under 40 feet above sea level along the Swimming River Reservoir and extending up Big Brook and Yellow Brook. The bulk of the Township is under 120 feet in elevation with the highest elevations exceeding 240 feet at two points; one in the extreme northwestern corner of the Township and the other, although too small to show on the map, in the N.W.S. Earle property in the south.
In conjunction with the topographic data, an evaluation of steep slopes was done to indicate areas where slopes are 10-15 percent and those over 15 percent. (A 15 percent slope indicates a vertical rise of 15 feet within 100 feet horizontally). When the data on slopes and elevations is compared, it becomes clear that aside from the steep slopes in the stream corridors, the northwestern area of the Topwnship has the greatest concentration of higher elevations and slopes exceeding 10 percent. Their existence is an indication of the erodibility of the soils and the need to carefully evaluate development proposals where the slopes exceed 10 percent. While steep slopes need not preclude development, vegetative stripping and regrading which would alter the runoff pattern and divert existing natural drainage to other areas must be recognized as creating a threat of erosion. Erosion into the reservoir will severely reduce the capacity of the reservoir by filling it with sediment rather than water.
Soil Conservation Service information was also utilized to develop Plate 3, Soils With Wet Characteristics. This plate indicates areas within stream corridors (flood plain or marsh) and the Swimming River Reservoir. (flood plain or marsh). Wet soils considered unsuitable for development are also shown. These wet soils are most prevalent in and around the N.W.S. Earle property and at the headwaters of several streams. In addition, this map also indicates areas considered "unsuitable for development unless sanitary sewers are provided." These lands have periodically wet characteristics or are on slopes of between five and ten percent. (While not shown, many areas with slopes in excess of ten percent are considered unsuitable for development unless sewers are provided because an increased incidence of effluent emerging from the soil on the downhill side can be expected). The major stream and drainage pattern is apparent from the configuration of the flood plain and marsh areas. South of Route 537 there are extensive wet areas and other areas considered unsuitable for development unless sewers are provided. In the area north of Route 537, there is an intermingling of soils considered suitable for development either with or without sewers. To a considerable extent, the flood plains, wetlands, steep slopes, and soils requiring sewers are so intermixed that careful designing of subdivisions and detailed site selection is essential in order to anticipate the capacity of the soils to accept sewage, provide potable water from on-site wells, provide proper street access, and allow building siting and driveways without creating potential problems.
Plate 4, Drainage Characteristics, is a map prepared from the Engineering Soils Survey of New Jersey (Report No. l9, Monmouth County). There are two major elements to the information contained in this material. The first is the drainage pattern indicating the "poor to imperfect" areas along the major drainage courses and in the flat, wetlands in the southern portion of the Township. Intermixed with these areas are the "imperfect to good" drainage characteristics which generally abut and enlarge the areas in the poor to imperfect categories. The second major element is the extent to which marl can be found throughout Monmouth County and in certain soil types within Colts Neck. This data can only be obtained from on-site inspections and borings. Because of the extent of marl, clay, and other heavy textured soils at various depths below the ground surface in this area of the state, detailed site information should be obtained before any site is approved for development. Perched water tables are sometimes found and if marl or clay has formed a subterranean deadpan, percolation does not take place below that layer and sewage and/or ground water often moves laterally until it finds a break in the deadpan and can continue to percolate or possibly reach an exposed area on the side of a hill where it will seep out of the ground into the surface water. In other locations, the effluent can accumulate under ground and saturate the earth. These characteristics indicate how the soils can place limitations on development.
The National Wetlands Inventory prepared by the U.S. Department of the Interior, Fish and Wildlife Service provides a general indication of the areas of "Wetlands". They are not shown in this Plan. When these maps were first published, they were the only data available. As site specific mapping began to be presented as part of subdivision and site plan applications, and the boundaries were set according to the three parameter requirements of the NJDEPNJ DEP. It became apparent that the National Wetlands Inventory was, at best, a broad indicator of where wetlands could be expected. For the most part those maps can be expected to be conservative in their boundary delineations. The actual wetland boundaries can be expected to be larger than shown on the National Wetlands Inventory, and wetlands can be expected to be found in areas not even shown on those maps.
In New Jersey, the state's Freshwater Wetlands Protection Act preempts local ordinances as to wetland regulations. The Act became effective July 1, 1988 followed by the requirement for transition areas effective July 1, 1989. Freshwater wetlands are defined as areas that are "....inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support......a prevalence of vegetation typically adapted for life in saturated soil conditions...." (NJ Freshwater Wetlands Protection Act). Wetland boundaries are determined by NJDEPNJ DEP based on site specific data according to the 3-parameter approach, i.e. hydrology, soils and vegetation. Wetlands are classified as an exceptional resource value when they discharge into trout production waters or their tributaries or if they provide a habitat for a threatened or endangered species. Wetlands are classified as an ordinary resource value if they are isolated wetlands not surface tributary to an inland lake or pond and are more than 50 percent surrounded by development and less than 5,000 sf in size, or are drainage ditches, swales, or detention facilities. Wetlands of intermediate resource value are all other wetlands. The significance of the determination of the value of the wetlands has to do with the transition area that is required for each. A transition area of 150 ft is required around a wetland of exceptional value, whereas an area of 50 ft is required around intermediateordinary wetlands. These transition areas must be provided even if the wetland is off-tract, but within the designated distances, except that NJDEPNJ DEP may grant waivers down to 75 ft and 1025 ft, respectively and NJDEPNJ DEP may approve an overall plan that averages the width of the transition area, e.g. reducing the transition area in one location and enlarging it in another.
Under the regulations, activity is severely limited in wetlands and their transition areas. Essentially, development has to avoid these areas. The regulated activities in wetlands are broadly stated as the removal, excavation, disturbance or dredging of soil, sand, gravel, or aggregate material of any kind; the drainage or disturbance of the water level or water table; the dumping, discharging, or filling with any materials; the driving of pilings; the placing of obstructions; or the destruction of plant life which would alter the character of a freshwater wetland, including the cutting of trees except the approved harvesting of forest products.
Due to the severe restrictions in wetlands and their transition areas, and considering the severity of the soil conditions in the "critical" areas, those portions of the "critical" areas outside of any wetlands as well as the wetland transition areas should not be developed. Most are extremely wet, some in flood hazard areas, some in freshwater wetlands and their related transition areas, and still other areas are highly susceptible to erosion due to erodable soils located along steep slopes. If these areas are proposed for development, it is likely that either the Freshwater Wetlands Act might preclude the development, or the cost of overcoming the natural limitations might either preclude the development mightor make the project economically infeasible. These "critical" areas should be designed within the developments as open space areas, or buffers, in order to be an integral part of the project, but the regrading and placement of the buildings and pavement should be elsewhere. Occasionally, it may be necessary to provide access roads across these areas. But as much as possible, these crossings should be avoided in order to minimize costly bridge construction, more expensive road cross sections, possibly higher road maintenance costs, and the impacts to the natural systems that would occur.
Data from the Soil Conservation Service also permitted an evaluation of areas suited for general agricultural use. Plate 5, Agricultural Soils, indicates that virtually the entire Township north of the N.W.S. Earle property falls within the top three agricultural classifications, excluding the flood plains and steep slopes. It is recommended that cluster zoning and other design options be considered in order to more strongly direct streets and buildings to Class III or lower agricultural classifications so the yards and dedicated open spaces are placed in the Class I and II agricultural soils as much as possible. Done in large enough patterns, this will encourage buffer areas between new development and existing farm activities thereby fostering better compatibility between the uses and encouraging the continuation of active farming. It is pointed out that the Monmouth County Planning Board has designated Colts Neck as an area for continued agricultural use and low density development. This long- range goal is compatible with the soil characteristics for general agricultural use, the soil limitations for individual wells and septic systems, the active farming now in the Township, and the lack of sanitary sewerage and public water systems within the Township.
Finally, Plate 6, Critical Areas, was prepared as a composite of the previous data plus those wetland areas located outside of these critical areas as taken from the United States Department of the Interior, Fish and Wildlife Service (1984) maps. However, it is generally known that the wetland boundaries are conservative and cannot be relied upon until site-specific testing has been done. The overall map indicates the extent and configuration of the most severe limitations which the natural soil conditions impose on potential development. The worst conditions from both the Soil Conservation Service data, the Engineering Soils Survey of New Jersey, and the wetland maps are included. While there is a pattern of steep slopes, wetlands and flood plains following the major drainage courses, there is also a pattern of an intermingling of soil conditions that can create problems for development beyond these drainage ways and steep slopes. The best agricultural soils, and the wet soils that could accommodate development if sanitary sewers are provided, have been excluded. These have been excluded because soils that would require sewers can be overcome with technological improvements. The continued preservation of agricultural soils is, in part, a policy decision. The extent to which the best agricultural soils might be preserved by either some governmental jurisdiction or preserved through a variety of design options in the Development Regulations Ordinance continue to be the two basic approaches that should be considered as a means of agricultural preservation.
It is estimated that 37 percent of the Township is included in the critical areas with 23 percent considered suitable for development only if sanitary sewers are provided. Considering some overlap in these two categories, about 50 percent of the Township is influenced by these conditions.