APPENDIX D: NATURAL RESOURCES

INTRODUCTION

The geological, hydrological, and biological characteristics of a community form the foundation and the framework within which a community can plan for future development. This natural resource base provides both opportunities and constraints for development and preservation. Failure to recognize the constraints or take advantage of the opportunities can result in a degradation of both the natural and cultural environment. It is essential to identify the areas of town that can accommodate development based on soil conditions, elevation, and an adequate water supply. In addition, the abundance and diversity of natural resources in Mont Vernon (wetlands, ponds, streams, fields and forests) provide opportunities for a variety of land uses while contributing to the overall quality of life in the community. Improper shoreline buffers will have negative impacts on water quality and the general character of the Town’s wetlands, streams, and ponds. Therefore, a thorough understanding of the natural resource base is extremely important in determining the limits of growth and guiding future development in the community. This chapter contains an inventory of Mont Vernon’s natural resources along with a discussion and analysis of current policies and regulations affecting resource conservation. Recommendations for future management of the Town’s natural resources are made at the end of the chapter.

The 1999 Community Profile and the Regional Environmental Planning Program (REPP) identified trails and the preservation of rural character as town priorities. After the Community Profile a Trails Committee was formed and an existing trails map is in the process of being updated. The top town priority identified in the REPP report is a proposed greenway trail system that would connect existing protected lands with new trails to connect to existing trails that meander through Mont Vernon. Also ranking high was preserving ground water supply, wetlands, forests, conservation land, wildlife habitat, and scenic roads.

B. Topography

Topography is the general form of the land surface, with elevation and slope as its major components. The lowest elevation in Mont Vernon is 330 feet above mean sea level, near the Milford border. Elevations are generally well above the 550 foot level. The steeper slopes and higher elevations are along the northern border, with the highest being Roby Hill, 1,001 feet above mean sea level. Elevation itself does not constrain development, but higher elevations in Town are more difficult to develop because they tend to have steeper slopes and shallower soils.

Slope is a critical determinant of the land’s ability to support certain land uses. Slope is generally divided into five categories, 0-3%, 3-8%, 8-15%, 15-25% and greater than 25%. Increases in slope result in corresponding increases in the difficulty and cost of site development. Areas with 0-8% slopes, representing 35% of Mont Vernon’s acreage, are easily developed. However problems with drainage may arise in areas with slopes less than 3%. Approximately 40% of the land has 8-15% slopes which have a moderate capability for development and may require additional engineering and construction considerations. While areas with 15-25% slopes are developable, shallow soils and increased potential for erosion require site specific considerations to alleviate negative impacts. This represents 47% of Mont Vernon’s acreage.

Land areas with slopes greater than 25% are considered undevelopable because of shallow soils, increased erosion potential, complexity of road and site construction, and inability to support on-site waste disposal systems. Slopes are a critical factor when siting septic systems to ensure adequate drainage and filtration.

C. Soil

Soil type is the principal determinant of the land’s development capability, especially since Mont Vernon relies upon subsurface waste disposal. Depth to water table and bedrock, susceptibility to flooding, slope, stone cover, and permeability are factors affecting the suitability of a site for roads, buildings, and septic systems.

The USDA Soil Conservation Service (SCS) (now known as the Natural Resources Conservation Service, or NRCS) conducted extensive surveys and analyses of soil conditions in Hillsborough County during the 1970s and published the Soil Survey of Hillsborough County, New Hampshire, Eastern Part in 1979. The Soil Survey delineates soil boundaries and provides information on the characteristics of individual soil types. This information should be used to make general land use planning and management decisions in a community, but site specific decisions may require additional on-site investigations. The Soil Survey includes information on the suitability of a soil for building sites, roads, septic tank absorption fields, wildlife habitat, recreation, agriculture, silviculture (tree farming), and construction materials. Soils are generally rated as having slight, moderate, or severe limitations for a particular use.

1. Soil Potentials for Development

In addition to the Soil Survey, the Hillsborough County Conservation District in conjunction with the SCS developed the Soil Potentials for Development, Hillsborough County, New Hampshire in 1986. This system rates soils based on soil properties and the quality of the soil for development compared with other soils in the County. The soils are divided into five development potential classes (very high, high, medium, low, and very low) for three development activities: septic tank absorption fields, local roads and streets, and dwellings with basements. A fourth category, overall development potential, is an average of all three.

The rating classes are defined in terms of the expected performance of a soil if feasible measures are taken to overcome its limitations, the cost of the measures and the magnitude of the limitations remaining after the corrective measures have been applied. Corrective measures can include siting on another portion of the lot, grading, and the addition or deletion of soils and gravel. Each soil is compared to a reference soil, a soil with the most favorable conditions for development, and evaluated for corrective measures, continuing limitations, performance, design criteria and cost estimates for overcoming limitations. Points are assigned based on the analysis with 100 being the highest rating a soil could receive. A soil that receives a moderate rating under the Soil Survey method could receive a high or very high rating under the Soil Potentials system if the problematic soil condition could be dealt with through design at a reasonable cost. Based on this, the Soil Potentials system more accurately represents the development capability of the land.

Because Mont Vernon relies totally on septic systems, the soil potential for septic tank absorption fields has the greatest impact on development capability. Based on the soil potential ratings for septic tank absorption fields, approximately sixty percent of soils in the Town receive a medium, low or very low rating. This does not mean that these areas are undevelopable; however, any proposals for development in these soils should receive close scrutiny Table 1 contains a list of the soil types in Mont Vernon and their potential for development of septic systems. There are 1,694 acres or 49% of undeveloped land left in Mont Vernon with high septic potential.

It has been common practice for communities to require that soil maps and information be submitted as part of a completed application for subdivision or site plan review. These maps are prepared by a certified soil scientist in accordance with either the High Intensity Soil Map Standards (HISS) or the Order 1 Soil Map Standards. Both Standards are currently being phased out of use by the year 2002. The Society of Soil Scientists of Northern New England has recently combined the better features of both soils mapping techniques into Site Specific Soil Mapping Standards (SSSMS). The SSSMS meet the criteria of the National Cooperative Soil Survey of the USDA/NRCS. This means that maps prepared in accordance to the SSSMS classify soils to the series level, which is consistent with the maps found in the county soil surveys. The SSSMS are the most current standards available that can be used for a variety of land use activities.

Permeability is another soil characteristic that is important to consider when siting septic systems. Permeability is the rate of downward movement of water through a saturated soil measured in number of inches per hour. The two permeability categories of concern are rapid and very rapid, 6-20 inches and more than 20 inches per hour respectively. Soil with these rapid permeabilities will transmit water quite rapidly, meaning that contaminants can easily and quickly reach surface waters and groundwater. Because of this, soils with rapid and very rapid permeability are poor filters for septic system effluent as indicated in the Soil Survey. Soils in Mont Vernon with rapid or very rapid permeabilities are marked with an asterisk in Table1.

Table 1 - Soil Potential for Septic systems

 

Soil symbol, name and slope

 

Soil symbol, name and slope

   

Soils with very high potential for septic systems

Soils with very low potential for septic systems

CaB

Canton fine sandy loam, 3-8%

BoA

Borohemists, nearly level

CaC

Canton fine sandy loam, 8-15%

BpA

Borohemists, ponded

CmB

Canton stony fine sandy loam, 3-8%

CmE

Canton stony fine sandy loam, 25-35%

CmC

Canton stony fine sandy loam, 8-15%

CsC

Chatfield-Mont Vernon complex, 8-15%

CnC

Canton very stony fine sandy loam, 8-15%

CtD

Chatfield-Mont Vernon rock outcrop complex, 15-25%

 

Total Undeveloped acres: 1,931.062

CpB

Chatfield-Hollis-Canton complex, 3-8%

Soils with high potential for septic systems

Cu

Chocorua mucky peat

CnD

Canton very stony fine sandy loam, 15-35%

   

CaD

Canton fine sandy loam, 15-25%

HsD*

Hinckley loamy sand, 15-25%

CmD

Canton stony fine sandy loam, 15-25%

LtA

Leicester-Walpole complex, 0-3%

WdB*

Windsor loamy sand, 3-8%

LtB

Leicester-Walpole complex, 3-8%

WdC

Windsor loamy sand, 8-15%

So*

Scarboro mucky loamy sand

MoC

Montauk fine sandy loam, 8-15%

   

MoD

Montauk fine sandy loam, 15-25%

   

MtB

Montauk stony fine sandy loam, 3-8%

Sr*

Scarboro stony mucky loamy sand

MtC

Montauk stony fine sandy loam, 8-15%

WdD

Windsor loamy sand, 15-25%

MtD

Montauk stony fine sandy loam, 15-25%

   

Soils with medium potential for septic systems

   

CpB

Chatfield-Mont Vernon-Canton complex, 3-8%

PiA

Pipestone loamy sand, 0-3%

CpC

Chatfield-Mont Vernon-Canton complex, 8-15%

PiB

Pipestone loamy sand, 3-8%

WvB

Woodbridge stony loam, 3-8%

Pp

Rippowam fine sandy loam, 3-8%

WvC

Woodbridge stony loam, 8-15%

LeA

Leicester Variant loam, 0-3%

StA

Scituate stony fine sandy loam, 0-3%

   

StB

Scituate stony fine sandy loam, 3-8%

   

StC

Scituate stony fine sandy loam, 8-15%

LvA

Leicester-Walpole complex, 0-3%

HsB*

Hinckley loamy sand, 3-8%

LvB

Leicester-Walpole complex, 3-8%

HsC*

Hinckley loamy sand, 8-15%

Pr

Pits, gravel

PfB

Paxton stony fine sandy loam, 3-8%

RbA

Ridgebury loam, 0-8%

PfC

Paxton stony fine sandy loam, 8-15%

ReA

Ridgebury stony loam, 0-3%

PfD

Paxton stony fine sandy loam, 15-25%

ReB

Ridgebury stony loam, 3-8%

PfE

Paxton stony fine sandy loam, 25-35%

 

Total Undeveloped Acres: 323.240

PbB

Paxton fine sandy loam, 3-8%

   

PbC

Paxton fine sandy loam, 8-15%

   

PbD

Paxton fine sandy loam, 15-25%

   

Total Undeveloped Acres: 805.192

   
 

Soils with low potential for septic systems

   

CpD

Chatfield-Mont Vernon-Canton complex, 15-25%

   

CsB

Chatfield-Mont Vernon complex, 3-8%

   

DeA*

Deerfield loamy fine sand, 0-3%

   

SsA

Scituate fine sandy loam, 0-3%

   

SsB

Scituate fine sandy loam, 3-8%

   

SsC

Scituate fine sandy loam, 8-15%

   

WoA

Woodbridge loam, 0-3%

   

WoB

Woodbridge loam, 3-8%

   
 

Total Undeveloped Acres: 423.734

   

Source: Hillsborough County Conservation District, Soil Potentials for Development, Hillsborough County, March 1986.

* Indicates soils with rapid or very rapid permeabilities

  1. Construction Materials

The Soil Survey also provides information about soils as a source of construction materials, or sand and gravel. Soils are rated as probable or improbable sources of sand and gravel based on gradation of grain sizes, thickness of suitable material and rock content. The soils listed in Table 2 are probable sources of sand or gravel in Mont Vernon. The Town does not address Excavation of sand and gravel resources in the Zoning Ordinances. This is treated as a Special Exception regulated under RSA 155-E, Local Regulation of Excavations. The statute requires that municipalities provide "reasonable opportunity for excavation" of construction materials on unimproved land within the community. During the housing construction boom years in the 1970’s and 1980’s, there were several sand and gravel excavations located in the southwestern section of Town. As of this writing, no permitted excavation is in operation in Mont Vernon.

 

table 2 - probable sources of sand and gravel

 

Soil symbol, name and slope

Sand

Gravel

CaB

Canton fine sandy loam, 3-8%

x

 

CaC

Canton fine sandy loam, 8-15%

x

 

CaD

Canton fine sandy loam, 15-25%

x

 

CmB

Canton stony fine sandy loam, 3-8%

x

 

CmC

Canton stony fine sandy loam, 8-15%

x

 

CmD

Canton stony fine sandy loam, 15-25%

x

 

CmE

Canton stony fine sandy loam, 25-35%

x

 

CnC

Canton very stony fine sandy loam, 8-15%

x

 

CnD

Canton very stony fine sandy loam, 15-35%

x

 

Cu

Chocorua mucky peat

x

 

DeA

Deerfield loamy fine sand, 0-3%

x

 

HsB

Hinckley loamy sand, 3-8%

x

x

HsC

Hinckley loamy sand, 8-15%

x

x

HsD

Hinckley loamy sand, 15-25%

x

x

PiA

Pipestone loamy sand, 0-3%

x

 

PiB

Pipestone loamy sand, 3-8%

x

 

So

Scarboro mucky loam sand

x

 

StA

Scituate stony fine sandy loam, 0-3%

x

 

StB

Scituate stony fine sandy loam, 3-8%

x

 

StC

Scituate stony fine sandy loam, 8-15%

x

 

Sr

Scarboro stony mucky loam sand

x

 

WdB

Windsor loamy sand, 3-8%

x

 

WdC

Windsor loamy sand, 8-15%

x

 

WdD

Windsor loamy sand, 15-25%

x

 

Source: Soil Conservation Service, Soil Survey of Hillsborough County, New Hampshire, Eastern Part, 1981.

3. Important Farmland Soils

High quality or prime farmland is a valuable and limited resource. In an effort to protect quality agricultural land and to slow its conversion to other uses, the SCS developed a classification system to identify prime farmland based on soil properties, temperature, growing season and moisture supply. Prime farmland soils are those that are best suited to crop production and will produce the highest yields with minimal inputs of energy and economic resources while causing the least amount of environmental damage. Mont Vernon should use this information to identify important agricultural areas and to plan for future management and protection strategies. Prime and statewide important farmland soils in Mont Vernon are listed in Table 3 and depicted on the map.

Prime and statewide important farmland soils comprise approximately 16% of the total land area in Mont Vernon. These soils are located throughout the Town, and not surprisingly coincide with many of the active agricultural operations. In addition to its importance for crop production, agricultural land use is an important form of open space in Mont Vernon. The open fields, farm buildings and activities provide a charming pastoral landscape for residents and visitors.

 

table 3 - State and Prime Designated farmland soils

 

Soil symbol, name and slope (State)

 

Soil symbol, name and slope (Prime)

CaB

Canton fine sandy loam, 3-8%

PbB

Paxton fine sandy loam, 3-8%

CaC

Canton fine sandy loam, 8-15%

WoA

Woodbridge loam, 0-3%

CpB

Chatfield-Hollis-Canton complex, 3-8%

WoB

Woodbridge loam, 3-8%

PbC

Paxton fine sandy loam, 8-15%

CmD

Canton stony fine sandy loam, 15-25%

MoC

Montauk fine sandy loam, 8-15%

   

SsA

Scituate fine sandy loam, 0-3%

   

SsB

Scituate fine sandy loam, 0-8%

   

SsC

Scituate fine sandy loam, 8-15%

   

Source: Hillsborough County Conservation District, Soils Potentials for Development, Hillsborough County, March 1986.

D. AGRICULTURE/FARM LAND

By the middle of the nineteenth century, agriculture reached its peak in southern New Hampshire. Approximately 55-65% of Hillsborough County was considered improved farmland at that time; most located in upland areas. Active agricultural practices, horse properties, and properties that are not actively managed as farms but are passive open spaces comprise over a 1,552 acres (14% to total acres in town) throughout Town, and are listed in Table 4. Agriculture in Mont Vernon has diminished over the years, and old stone walls in the forests are the only clues to the formerly cultivated lands. The rural picturesque quality attracts new residents to Mont Vernon. Yet residential development pressure is the very thing that threatens the existence of Mont Vernon’s remaining farmlands.

Table 4 - Mont Vernon Farmland and Acreage

Active Farms

Dairy

105.3

Leased Cow Pasture

5.0

Dairy Cropland Support-Hay

100.0

Dairy Cropland Support-Corn

50.0

Farm Leased for Dairy Grazing

32.2

Sheep

3.7

Goats

4.9

Buffalo

10.0

Beef Cattle

90.0

Llamas

95.4

Vegetables

8.0

Christmas Trees

16.0

Christmas Trees

19.0

Sub Total Active Agriculture

535.8

Horse Properties

Horses

10.0

Horses

7.4

Horses

24.2

Horses

222.1

Horses

40.0

Horses

11.4

Horses

25.0

Sub Total of Horse Properties

340.1

 

Open Space with "Farm Appearance"

Lamson Farm

331.5

Unmaintained Apple Orchard

135.9

"Farm Appearance" Open Space

46.0

"Farm Appearance" Open Space

13.0

"Farm Appearance" Open Space

12.5

"Farm Appearance" Open Space

72.5

"Farm Appearance" Open Space

7.5

"Farm Appearance" Open Space

20.0

"Farm Appearance" Open Space

4.5

"Farm Appearance" Open Space

30.0

Open Space Sub Total

Total 1,552 acres (14% total of town acreage)

345.6

Source: The Mont Vernon Master Plan Committee

Based on the Community Profile, maintaining agricultural land is a high priority. For agriculture to remain in Mont Vernon, the Town must develop innovative regulations, programs, and policies beneficial to everyone. One method would be to acquire easements or purchase development rights to preserve agricultural uses. The Town should also seek additional funding sources both inside and outside its own budget to support agriculture. The Land and Community Heritage Investment Program is a good example of such funding. Monies may also become available through the Conservation and Reinvestment Act (C.A.R.A. 701) for farmland preservation. In addition, there is a "Barn Again" Program, which aids rehabilitation and preservation of incoming producing barns.

 

E. FOREST RESOURCES

Forests were the dominant landscape characteristic after the retreat of the glaciers. Before 1623 and the colonization of New Hampshire, southern New Hampshire was 93% forested, with the 7% open space being marsh or ponds. Many major changes have affected the ecosystem in southern New Hampshire since that time. By 1850, at the height of agricultural development in New Hampshire, only 20% was forest, while the remaining 80% of Hillsborough County was cleared for livestock grazing, growing livestock feed, and other crops for home consumption. Most of the changes historically are associated with population and economic opportunities. Agriculture began to decline during the 1860’s with the western migration and industrialization of the northeast. The Amoskeag Mills in Manchester (incorporated in 1831 and by 1910 was the largest textile mill in the world, employing 17,000 workers ) and the mills in Lowell and Lawrence drew workers (particularly females) from rural communities to the cities. These fields slowly gave way to scrub trees. Conifers generally took over the abandoned farmlands and meadows.

During the 20th century, foreign disease and pests have changed forest composition and were responsible for the decline or destruction of the American Beech, American Elm, and the American Chestnut. The introduction of the chestnut blight from Asia around 1904 killed most of the mature chestnuts within 20 years. According to the 1997 Integrated Natural Resources Management Plan for the New Boston Air Station, remnants of stands of chestnut trees have been discovered on the installation. The proximity of "Chestnut Hill" also suggests that chestnuts were prevalent throughout the entire area.

According to the Society for the Protection of New Hampshire’s document entitled "New Hampshire’s Changing Lands", reforestation began to stabilize during the 1960’s. The peak and downturn of forest cover began in the 1970’s and 1980’s when population gains and development increased throughout the state. Around 1983, New Hampshire reached an estimated high of 87% forest cover, which has not been seen since 1700. Satellite analysis in 1993 indicated that the forest cover was approximately 83%. This makes New Hampshire the second most forested state after Maine. The forest industry is the third largest in the state after tourism and manufacturing.

White pine has been the predominant tree harvested since colonial times. Hillsborough County is still a leader in white pine sawlog production. Red oak and sugar maple command a good market price. Deciduous (4,288 acres) and mixed (3,670) forest types are dominant in Mont Vernon comprising approximately 85% of total land cover in Town. Mixed, coniferous, and deciduous forests are widely scattered throughout the Town as depicted on the map.

Silviculture activities in Mont Vernon consist of predominately Christmas tree and firewood sales. There are currently two Christmas tree farms consisting of 16 and 19 acres respectfully. Firewood is still widely used as supplemental heat source in the winter. Small woodlots continue to be selectively cut as supplemental income. The most current clear cut of timber is the Lorden property which harvested approximately 600 acres in the southwestern section of Town. Performance standards and plan review for silvicultural activities are regulated by the State through timber harvesting and water quality laws. Regulation prohibits the placement of slash and mill waste in or near waterways, and limits clear-cutting near great ponds and streams. These requirements may mitigate to some degree water quality impacts associated with timber harvesting. There is no set policy on clearcutting in Mont Vernon, but the Conservation Commission continues to verbally negotiate buffers widths with loggers on a case by case basis.

 

f. Water Resources

Lakes and ponds, rivers and streams, wetlands and groundwater are the most obvious components of the hydrologic cycle. An understanding of the interrelationships between these components is essential for ensuring the wise use and management of Mont Vernon’s water resources. The quality and availability of surface water and groundwater is a factor in determining the development capability of a community. An ample, high quality water supply can ensure successful development of land for residential, agricultural, commercial, and industrial uses. The water resource network of a community also provides fish and wildlife habitats. It conveys and stores floodwater, recharges groundwater, generates power, and provides numerous recreational opportunities and unique scenic character. This section discusses Mont Vernon’s water resources and the major issues confronting their use and management.

1. Watersheds

A watershed is defined as that portion of the land area from which runoff contributes to the flow of a stream, river, lake, or pond. Watersheds are generally delineated by first identifying the highest points in the area. Lines called drainage divides are drawn between these points based on the topography and the direction of water flow. Land uses and other activities that take place within the watershed of a watercourse or water body have a direct impact on water quality and quantity. Extensive paved areas will increase the volume of surface runoff from a site. Land clearing and construction activities will expose previously undisturbed areas to erosive powers of rain and surface runoff. Delineation of the boundaries of a watershed facilitates the identification and evaluation of existing and potential water quality impacts of land uses upon a water body. When dealing with watercourses and water bodies that are exhibiting signs of stress, such as increases in turbidity or aquatic vegetation, it is important to identify the source or sources of the problem and to ameliorate or eliminate the impact.

The entire Town of Mont Vernon is located within the greater Merrimack River watershed, which covers 5,010 square miles in New Hampshire and Massachusetts. In Mont Vernon, there are five sub-watersheds, four of which drain into the Souhegan River Watershed as shown in Table 5. Purgatory and Beaver Brooks sub-basins are the largest. Precipitation from Purgatory Hill, Beech Hill, and Black Brook flow into Purgatory Brook, which flows south through Milford. Portions of Kendall Hill, Weston Hill, and McCollom Hill feed Beaver Brook, which flows in a southeasterly direction into Amherst. Hartshorn and Joe English Brook also flow in a southeasterly direction and drain to the Souhegan River. Precipitation falling on the west side of South Hill and Storey Hill flows into Lords Brook which drains to the South Branch of the Piscataquog River.

 

Table 5 - Watersheds in Mont Vernon

Name

Location

Total Watershed Acres in Square Miles (mi2)

Mont Vernon Acres in Square Miles (mi2)

Purgatory Brook

West

4,730 (7.4)

3,453 (5.4)

Lords Brook

Northwest

1,453 (2.3)

1,382 (2.2)

Beaver Brook

East

8,431 (13.2)

3,457 (5.4)

Hartshorn Brook

Central

2,290 (4.6)

1,533 (2.4)

Joe English Brook

East

6,604 (10.3)

832 (1.3)

 

2. Perennial Streams

Over 18 miles of perennial streams flow through Mont Vernon, including portions of the five major named streams. Table 6 describes the perennial streams in Mont Vernon. Water quality classifications are established by the legislature. The classification represents the desired level of water quality for the stream and does not necessarily reflect actual conditions. In many instances water quality in a river or stream does not meet the standards of the legislative classification. This means they either meet or have a goal to achieve the fishable and swimmable criteria established under the Clean Water Act. There is no water quality information available for the segments within the Town.

 

TABLE 6 - perennial streams in Mont Vernon

Name

Location

Total Length

(miles)

Mont Vernon

Length (miles)

Lords Brook

Northwest

3.9

2.4

Beaver Brook

East Central

9.3

3.8

Hartshorn Brook

Central

4.0

2.8

Caesars Brook

Central

3.3

2.1

Black Brook

Northwest

1.6

1.3

Sources: USGS topographic maps.

 

3. Floodplains

Floodplains are areas adjacent to water courses and water bodies that are susceptible to flooding during periods of excessive runoff. According to the Federal Emergency Management Administration’s (FEMA) Flood Insurance Rate Maps (FIRMs) and the Flood Hazard Boundary Maps (FHBMs) there is only one floodplain in Mont Vernon adjacent to Purgatory Brook as shown on the map. This small strip is on the east bank and is designated Zone A, which is a special flood hazard area that can be inundated by a 100-year flood.

4. Shoreline Protection

The New Hampshire Shoreland Protection Act (the Act) also regulates uses within 250 feet of listed bodies of water. The Act establishes development and use standards around significant bodies of water. The Town can assume enforcement of the Act if it adopts the State’s model ordinance and has it approved by the Office of State Planning. There are no the bodies of water in Town that are protected under the Shoreland Protection Act, as determined by the New Hampshire Department of Environmental Services.

5. Ponds

Mont Vernon has five named ponds less than 10-acres. Horton Pond is the largest water body and is actively used for recreation. A result of a large beaver dam backwater, the area is a perfect spot to observe beaver activity. Wood duck boxes have been strategically placed to encourage nesting populations. There is a nice picnic spot on large outcropping of rocks. Although there are several houses in close proximity to the pond, most of the shoreland along the pond has not been developed for seasonal and year-round residential use. Horton Pond feeds Black Brook, which flows in a southwesterly direction to Purgatory Brook, which drains into the Souhegan River. Also, a small un-named stream flows in a southeasterly direction to Woods Pond. Stearns Pond is the headwaters of Hartshorn Brook, which flows in a southerly manner to the Souhegan River. The characteristics of the major ponds in the Town are summarized in Table 7.

 

table 7 - ponds in Mont Vernon

Name

Location

Acres

Elevation

Other

Stearns

Central

8.0

   

Hortons

Central

10.4

705

9ft deep

Woods

North central

5.6

   

Carlton (Jew)

central

.56

   

Roby

ICE POND

New boston air station (northeast)

.75

2.8

 

Dam

dam

Sources: NH Office of State Planning, Inventory of Lakes, Ponds, and Reservoirs, Biological Survey of Lakes and Ponds in Cheshire, Hillsborough and Rockingham Counties; U.S Geological Survey

8. Wetlands/Vernal Pools

The Wetland Conservation District in Mont Vernon are the areas identified and delineated as poorly or very poorly drained soils (hydric).. Soils in Mont Vernon that are commonly associated with wetlands are listed in Table 8. This includes bodies of water as defined by the current HISS maps for the State and the most recent U.S. Fish and Wildlife Plant Species List. Approximately 11% of total land (1,200 acres) in Mont Vernon contain hydric soils and are depicted on the map.

 

table 8 - wetland soils in Mont Vernon

 

Soil symbol, name and slope

 

Soil symbol, name and slope

BoA

Borohemists, nearly level

PiA

Pipestone loamy sand, 0-3%

BpA

Borohemists, ponded

PiB

Pipestone loamy sand, 3-8%

Cu

Chocorua mucky peat

RbA

Ridgebury loam, 0-8%

LeA

Leicester Variant loam, 0-3%

ReA

Ridgebury stony loam, 0-3%

LtA

Leicester-Walpole complex, 0-3%

ReB

Ridgebury stony loam, 3-8%

LtB

Leicester-Walpole complex, 3-8%

Rp

Rippowam fine sandy loam

LvA

Leicester-Walpole complex stony, 0-3%

So

Scarboro mucky loamy sand

LvB

Leicester-Walpole complex stony, 3-8%

Sr

Scarboro stony mucky loamy sand

Source: Hillsborough County Conservation District, Soil Potentials for Development, Hillsborough County, March 1986.

Generally, the term "wetland" means those areas of land that are inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. They include areas such as fresh marshes, wooded swamps, and vernal pools. Many of these areas are created by the seepage of groundwater to the land surface, though some are isolated from the groundwater system. Some receive, and subsequently produce surface drainage, while others simply catch and absorb precipitation.

Wetlands perform many beneficial functions including holding and slowly releasing storm water runoff, trapping sediments and allowing them to settle out, and filtering out excess nutrients dissolved in the water. These functions are particularly important in Mont Vernon, where all water comes from private wells.

Currently Mont Vernon requires a 25-foot buffer for all wetlands in the Wetland Conservation District. The following uses are permitted within the District if they do not result in the erection of a structure or alter the surface configuration by the addition or removal of fill; forestry and tree farming; agriculture; water impoundments and wells; normal drainage ways; wildlife refuges; parks and recreation areas; conservation areas and nature trails; open space and streets, roads, utility crossings or other access ways essential to the productive use of land.

In addition, wetland areas can only be used to satisfy twenty-five percent of the minimum lot area requirement. All septic systems and leach fields are required to be set back a minimum of seventy-five (75) feet from wetlands. Other uses may be permitted by special exception of the Zoning Board of Adjustment.

Regulatory methods for protecting wetlands from degradation include: requiring and enforcing erosion and sedimentation plans for developments; establishing minimum setbacks for buildings, structures, septic systems and other site developments; maintaining a vegetative buffer directly adjacent to the wetland; general education on the importance of wetlands; and prime wetland designation.

Vernal pools are temporary wetlands that fill with water sometime between fall and spring and are usually dry by late summer. Vernal Pools are known by many names such as spring ponds and ephemeral wetlands. These forest pools are essential for the life cycle of many invertebrates and amphibians. The nutrients from fallen leaves support a rich food web. The Committee recommends that an inventory of vernal pools be completed in the future.

 

9. Prime Wetlands

State law (RSA 482-A:15) authorizes a community to designate wetland areas meeting established standards as prime wetlands. The criteria and the submission requirements are explicitly set forth in the administrative rules governing the Wetlands Bureau. The benefits of prime wetland designation include:

A few points about prime wetlands should be noted. First, prime wetland designation can only apply to very poorly drained soils. Second, the Conservation Commission must notify the Wetlands Board when a proposal would involve a designated prime wetland. The Master Plan Committee recommends that the Town undertake a Prime Wetland inventory to give these wetlands additional consideration by the Wetlands Bureau when building proposals are presented to the Town.

10. Ground Water

Ground water from bedrock deposits provides water for most of the residential, agricultural, commercial, and industrial users in Mont Vernon. Bedrock wells are drilled into rock fractures that provide substantial volumes of water. Since 1984, the New Hampshire Department of Environmental Services (NHDES) has required that information be provided to them including but not limited to, the completion date, type of well, and depth. Well completion reports for 207 wells in Mont Vernon on file with NHDES Water Supply and Pollution Control Division, indicate a range in depth of 100 feet to 1,000 feet for bedrock wells. However, only 97 wells are on the map since the State data layers have not been updated since 1999. This equates to approximately 14 wells a year being drilled in Mont Vernon since 1984.

Stratified drift aquifers are composed of well-sorted sands and gravels, which generally have the potential to yield large quantities of water. Mont Vernon’s only aquifer is a small one located in the northwestern area of town. The 1987 United States Geological Survey study, Hydrology of Stratified Drift Aquifers and Water Quality in the Nashua Regional Planning Commission Area, described Mont Vernon’s stratified drift aquifers as follows:

Till deposits contain a mixture of clays, sands and gravels of varying grain sizes. These deposits do not have the capacity to store or transmit large volumes of water; however, they can provide sufficient volumes to supply individual residences.

There are no regulations in Mont Vernon that provide direct protection to groundwater resources. According to the NHDES Water Supply and Pollution Control Division there are six public water supply wells in Mont Vernon depicted on the map. This includes two at the Rolling Acres Mobile Home Park, the Village School, Town Hall, the McCollom Building, and the Mont Vernon Inn. Consideration should be given to test the closed well behind the Post Office as a source for present and future water supplies.

If planned properly, Mont Vernon residents may be able to continue to rely on the current water supplies produced by private wells and small public systems. However, it is necessary to prevent pollutants from entering these water supplies. Public education is an important part of maintaining the quality of our water, and efforts must continue to make that information readily available, especially as residents move into town accustomed to municipal water and sewer services.

 

e. Wildlife

Mont Vernon’s natural resource base provides a habitat for many plant and animal species. A variety of habitats such as wetlands, forests, fields, rivers, and streams are essential to support a diversity of species in quantities healthy enough to ensure continuation of the species. Maintaining quality habitats is crucial to the continuation of all plant and animal species.

The New Hampshire Natural Heritage Inventory (NHI), a program of the Department of Resources and Economic Development, tracks threatened and endangered species and exemplary natural communities in the State. Using a ranking system developed by the Nature Conservancy, the NHI assesses the rarity of a species on a global and state level. State listing ranks are defined by New Hampshire Code of Administrative Rules (RSA 217-A:3). The NHI records does not identify any natural communities in Mont Vernon However, the 1997 Argonne National Lab (ANL) Biodiversity Survey identified 9 natural communities on the New Boston Air Station. These areas, identified by the dominant plants, vegetative structure and minor features of the physical environment, represent intact examples of New Hampshire’s native flora and fauna.

 

1. Animals

Animal species commonly found in Mont Vernon include: raccoons, opossums, skunks, muskrats, beavers, porcupines, woodchucks, white-tailed deer, squirrels, mice, bats, foxes, rabbits, and other indigenous species that are adapted to living near humans and urban activities. There is a known deer yard in the southeast section of town. Sightings of coyote, otter, black bear, and fisher cats have increased in Mont Vernon as they have in other municipalities. Moose have also been sighted in recent years. Larger animals that require extensive habitat areas or species that require solitude such as black bears and are occasionally sighted in the Town. It is recommended that the Conservation Commission and interested citizens participate in the "Keeping Track" Program. This program uses animal tracks to identify habitats and feeding grounds in a systematic manner for a variety of animals. The information gained can be the start of an inventory and a monitoring system of prime habitats for future conservation.

 

2. Birds

Bird species vary according to the season: however, they are also dominated by those species commonly found in southern New Hampshire. Doves, woodpeckers, chickadees, and jays are found throughout the year while warblers, sparrows, hummingbirds, wrens, swallows, robins, and several species of raptors are generally seasonal residents. In addition there are owls, wild turkeys, woodcocks, spruce grouse, blue herons, pileated woodpeckers, cardinals, bluebirds, and red-tail hawks. Other species such as ducks and geese may nest in the wetlands and ponds and many pass through the Town during spring and fall migrations. The only species found in Mont Vernon that is listed in the NH Heritage Inventory as endangered is the Pied-Billed Grebe.

The "Watch List" is a program developed by the National Audubon Society to call attention to birds at risk before they require federal listing, stressing preventative action today over last ditch rescue attempts in the future. Many agency scientists (USFWS, DOD, Audubon) are involved in the Partners in Flight Program. The Partners in Flight Program is a similar program to the Watch List but on an international scale. The Audubon Watch List annually targets bird species with declining populations; species with limited ranges; and species facing threats such as habitat loss on their breeding grounds, wintering grounds, and migratory routes. The Watch List species listed in Table 9 were identified during the biodiversity study at New Boston Air Station. Since many of the same habitats can be found throughout Mont Vernon it is likely that the same species can be found in Town.

TABLE 9 - National Audubon Society’s Watch List

American Bittern

Grey Catbird

Black-billed Cuckoo

Field Sparrow

Yellow-billied Cuckoo

Prairie Warbler

Chimney Swift

Palm Warbler

Eastern Pewee

Bobolink

Veery

Wood Thrush

Source: Argonne National Lab 1997 Biodiversity survey of new Boston air station; Audubon Society’s Watch List

In addition to the highly visible species, habitats for other less visible species such as turtles, frogs, toads, salamanders, snakes and numerous insects are present in the Town. Vernal pools are temporary home to many of these species. Most vernal pool animals do not live their entire lives in the pool but migrate in response to seasonal ponding and drying. Most adult salamanders and frogs migrate to the pools to reproduce and the surviving juveniles leave before the water dries. Other organisms (e.g., snakes, turtles, insects, birds) migrate from nearby wetlands to breed or feed in the productive pool waters. These animals return to more permanent wetlands. The NHI only makes note of historical sightings of the spotted turtle in Mont Vernon.

3. Plants

Plant species in Mont Vernon are again dominated by those commonly found in southern New Hampshire. The NHI records indicate there are no threatened or endangered plant species in town. However, the New Hampshire Native Plant Protection Act identifies 11 plants as "special concern." These species are not rare in New Hampshire, but there showy nature makes them vulnerable to over collection. Table 10 identifies the species of special concern, many of which are found in Mont Vernon.

 

 

 

 

 

Table 10 - Plant Species of Special Concern

Grass Pink

white fringe orchis

Flowering Dogwood

large purple fringed orchid

pink lady’s slipper

rose pogonia

dutchman’s breeches

lapland rosebay

trailing arbutus

pitcher plant

mountain laurel

 

 

f. Conservation Lands

The Town of Mont Vernon contains a variety of conservation, recreation and public land under public and private ownership. These areas account for over 1,759 acres of the total land area in Mont Vernon. The Lamson Farm is the largest in town, with 316 acres, comprising roughly 18% of the conservation land. The Lamson Farm has plenty of old woods roads that are good for hiking and birdwatching. The annual Lamson Farm Days is one of the Town’s biggest and most popular events. Once a popular resort area, Purgatory Falls is now only accessible by hiking. Purgatory Brook flows through heavily wooded, pristine forest. The water surges through a deep flume before cascading into the pool below. The Mont Vernon Trails Committee has created a trail along most of the brook. Table 11 indicates vacant land according to parcel size. Some of these parcels are already protected but this map could be used as a planning tool to identify key parcels to connect existing conservation lands, provide wildlife corridors, and add to the proposed greenway.

The Town has also acquired a number of conservation easements over significant properties and adjacent to sensitive areas such as wetlands. These easements protect important natural and community areas while providing interconnections between the larger public parcels. In addition to the conservation lands under the more permanent forms of protection, 6,613.82 acres or 61.41% of land in town are enrolled in the "current use" program according to the 1998 New Hampshire Department of Revenue Assessment Report. The New Hampshire legislature has recognized the importance of open space and has found that its preservation is in the public interest:

It is hereby declared to be in the public interest to encourage the preservation of open space, thus providing a healthful and attractive outdoor environment for work and recreation of the State's citizens, maintaining the character of the State's landscape, and conserving the land, water, forest, agricultural and wildlife resources. It is further declared to be in the public interest to prevent the loss of open space due to property taxation at values incompatible with open space usage. Open space land imposes few if any costs on local government and is therefore an economic benefit to its citizens. (RSA 79-A:1)

Table 11 includes some of the most prominent and natural undeveloped areas in Mont Vernon. The preservation and conservation of these sites and areas is of tremendous importance to the preservation of the visual quality, water quality, farms and forests, wildlife habitats, greenways, trails and rural character of Mont Vernon.

The 1999 Community Profile and the Regional Environmental Planning Program (REPP) revealed that trails were a high priority. After the Community Profile, a Trails Committee was formed is currently updating the existing trails map. Shown on map are the top town priorities identified in the REPP report. The proposed greenway trail system would connect existing protected lands and establish new trails connecting to existing trails that meander throughout Mont Vernon. Also ranking high in the Community Profile was preservation of ground water supply, wetlands, forests, conservation land, wildlife habitat, and scenic roads.

 

TABLE10 - Protected Lands in Mont Vernon

property

Map and Lot #

Acres

sPNHF - KING

6-31, 6-32, 6-33, 6-34, 6-35

34.8 total

pURGATORY fALLS

3-43

1.4

cARLETON pARK

4-46

3.4

HORTON POND

4-27

9.8

PURGATORY FALLS

3-41-1

11.1

TOWN OF MONT VERNON

3-45

11.09

FRANCES HILDRETH TOWN FOREST

New boston

28.7 on town line

PURGATORY FALLS

3-43

27.4

TOWN OF MONT VERNON

1-1 check

33.1

HERLIHY SWAMP

7-55

43.9

TOWN OF MONT VERNON

6-1

32.5

HERBERT LOT

6-17

147.5

LAMSON FARM

7-4, 7-7, 7-74

316.5 total

TOWN OF MONT VERNON

1-16-101

16.3

TOWN OF MONT VERNON

1-82-001

5.0

TOWN OF MONT VERNON

1-83

0.5

TOWN OF MONT VERNON

1-84

7.6

TOWN OF MONT VERNON

1-10

28.7

TOWN OF MONT VERNON

1-18, 1-18-3, 1-18-11

21.3, 2.1, 1.4

TOWN OF MONT VERNON

1-34

2.0

TOWN OF MONT VERNON

1-38-001

2.2

TOWN OF MONT VERNON

10-34

2.0

TOWN OF MONT VERNON

9-62

0.7

TOWN OF MONT VERNON

9-50

3.0

TOWN OF MONT VERNON

9-49

0.34

TOWN OF MONT VERNON

9-55

0.19

TOWN OF MONT VERNON

9-20

3.3

TOWN OF MONT VERNON

4-75

3.2

Town of Mont Vernon

2-39

0.63

TOWN OF MONT VERNON

2-44

30.4

TOWN OF MONT VERNON

2-18-A-1, 2-18-A-2, 2-18- A-3

2.2, 2.0, 2.1

TOWN OF MONT VERNON

4-70-9, 4-70-10

2.0, 2.4

TOWN OF MONT VERNON

5-29

8.8

TOWN OF MONT VERNON

5-39

57.3

TOWN OF MONT VERNON

4-68-9, 4-68-10, 4-68-11, 4-68-12

14.3, 13.2, 0.41, 0.37

TOWN OF MONT VERNON

4-70-6

1.3

TOWN OF MONT VERNON

4-70-16, 4-70-17

14.7, 7.6

TOWN OF MONT VERNON

4-70-11

2.5

TOWN OF MONT VERNON

4-63

9.0

TOWN OF MONT VERNON

5-43

0.83

TOWN OF MONT VERNON

5-42

0.82

TOWN OF MONT VERNON

4-54-1, 4-54-2

11.9, 2.2

TOWN OF MONT VERNON

4-20-1

22.2

TOWN OF MONT VERNON

1-37

8.4

TOWN OF MONT VERNON

7-55, 7-55-01 3 w/o m/l

43.9, 6.3, 4.3, 5.1, 4.9

TOWN OF MONT VERNON

7-17, 7-17-6

12.4, 2.3

TOWN OF MONT VERNON

1-68

0.35

TOWN OF MONT VERNON

2-65, 2-65-1

8.8, 0.45

TOWN OF MONT VERNON

7-4

48.3

TOWN OF MONT VERNON

7-77

3.4

TOWN OF MONT VERNON

6-42

63.6

TOWN OF MONT VERNON

4-16

33.9

TOWN OF MONT VERNON

7-60-13, 7-60-13-7

3.7, 1.2

TOWN OF MONT VERNON

2-52

3.3

TOWN OF MONT VERNON

4-55

7.2

SATELLITE TRACKING FACILITY

8-10 in mont vernon

488

 

gRAND TOTAl ACREAGE

1759.98

SOURCE: Town of Mont Vernon Land Assessment Records

 

New Boston Air Station

The New Boston Air Station is slated as a base closure within the next ten years. Changes to the Mont Vernon Zoning Ordinance at Town Meeting included the adoption of a Managed Commercial and Conservation Zone to enable compatible development within the portion of the New Boston Air Station (NBAS) located in the municipal boundaries of the Town of Mont Vernon. This represents 488 acres of the approximately 2,849 acre United States Air Force (USAF) installation located in the towns of Amherst, Mont Vernon, and New Boston. Each of the towns have been working on plans for their portion of the installation. This large undisturbed tract will be an asset to the Town’s conservation holdings. However, Mont Vernon’s only access to the property is off Tater Road at this time.

Forest Resources

The predominant land use in the NBAS area from settlement until acquisition by the Federal government was small and large-scale farming. Aerial photographs taken in 1941 showed most of the farmland was reverting back to forest. NBAS has approximately 2,375 acres of forest that can be managed using standard forestry practices. MBAS’ 1998 Integrated Forestry Plan (Plan) uses a community or ecosystem approach in which all species are considered important parts of the forest as opposed to the 1993 Plan which gave management priorities to species with high commercial value. No additional forest roads will be built to avoid forest fragmentation. Timber harvesting will be prohibited in all areas containing rare natural communities and threatened and endangered species identified in the 1997 Biodiversity Survey.

Wetlands

The major wetlands located in Mont Vernon section of the NBAS are around Joe English Pond and the Ice Pond drainage area into Joe English Pond. Throughout the NBAS there are 119 Palustrine Forested (PFO) wetlands due to irregular topography and extensive evergreen forests. They include deciduous forests (PF01), evergreen forests (PF04), and mixed forest (PF01/PF04) areas. Many small isolated wetlands did not show up on the aerials but are known to exist. There were 21 Palustrine Emergent (PEM) wetlands identified. Emergent wetlands are characterized by erect, rooted, herbaceous hydrophytes, excluding mosses and lichens. The formation of most of these wetlands has been from beaver activity.

Current Native Vegetation

Ninety eight percent of the NBAS remains covered with native vegetation. A total of 454 species of plants were identified in the 1997 Argonne National Lab (ANL) biodiversity survey conducted over a three year period. No federally listed threatened or endangered plants were found on the station. However, the fern-leaved false foxglove is listed by the State of New Hampshire as endangered. Five additional species listed by the state as species of special concern include pink lady’s slipper, trailing arbutus, mountain laurel, rose pegonia, and pitcher plant.

Native Fauna

A total of 147 species of birds have been recorded at NBAS during the ANL biodiversity survey; 109 were neo-tropical migrants. The only federally listed (threatened) species was the bald eagle. The eagle was spotted during the fall migration and is known not to use the habitat on the base. Several state listed species were observed and included: pied-billed grebe (endangered), osprey (threatened), Cooper’s hawk (threatened), and northern harrier (threatened). The harrier was observed during fall migration.

The base contains six ponds, one man-made (Seavy Pond) and five existing wetlands that were dammed to raise water levels. All of the ponds have good water quality but are susceptible to the annual buildup of coliform bacteria during dry periods in the summer. There are at least eight species of fish; two species of trout (Brook, Rainbow) are stocked in the larger ponds (Joe English, Roby, Ice) to provide a recreational fishery.

Eight reptile species have been recorded at NBAS none of them federally or state listed. Twenty-two species of mammals have been recorded. No critical habitat has been designated at the installation. However, several rare natural communities designated by the New Hampshire Natural Heritage Inventory were identified at the installation are listed in Table 12.

TABLE 12 - Rare Natural Communities

Black Gum-Red Maple Swamp

Southern Acidic Rocky Summit Community

Oak-Pine Rocky Summit Community

Coastal/Southern Acidic Fen

Coastal/Southern Dwarf Shrub Bog & Acidic Fen

Hardwood-Conifer Basin Swamp

Coastal/Southern Dwarf Shrub Bog

Dry Transitional Oak-White Pine Forest

Transitional/Appalachian Acidic Talus Woodland

Source1998 Integrated Natural Resources Plan for NBAS

g. Visual Resources

The visual resources of a community are a major component of its image and sense of place, and have an impact on the quality of life for residents and the perceptions of visitors. The Town of Mont Vernon is well aware of the value of its natural resources: ponds, streams, wetlands, and forests, its orchards and active agricultural lands, and its built environment – the Town center, historic homes, and other buildings and structures. Table 13 contains the views identified that are exceptional and should be left undisturbed.

Reasonable protection of outstanding views and vistas has withstood the test of the courts on numerous occasions throughout the country. Typical view protection regulations involve height limitations for buildings and structures and/or setbacks. Height limitations have been used to preserve views of natural features such as mountain peaks, park areas and river views, and for protecting the stature of historic structures and landmarks

 

Table 13 - scenic Views of Mont Vernon

Scenic View

Direction

Scenic View

Direction

Grand Hill

South

Old Milford at Trow Road

 

Mason Road

 

Kittridge Road

South

Lamson Farm

 

Behind Post Office at the top of the cornfield

North

Village School Library

South

Old sawmill ruins near Secomb Road

West

Top of Route 13

South

Purgatory Falls

South

End of Smith Road

Southeast

Horton’s Pond

 

Old Amherst Road & Carleton Road

Southeast

Herlihy Swamp

 

View of Joe English Ledge

Northeast

   

The State of New Hampshire, recognizing the importance of its scenic roadways, enacted RSA 231:157 granting communities the authority to designate local scenic roads. The law is an important tool in protecting the scenic qualities of roads. Scenic roads are special designation of Class IV, V, and VI roads where cutting or removal of a medium and large-sized trees, or disturbance of a stone wall, must go through the hearing process and written approval of local officials. Setbacks are also commonly used to protect scenic roadways. Table 14 contains a list of the scenic roads in Mont Vernon. Class VI roads or un-maintained highways, consist of all other existing public ways, including highways subject to gates and bars, and highways not maintained in suitable condition for travel for five years or more. See Table14 and the map for the designated Class VI roads located in Mont Vernon.

The Planning Board should consider the impact of developments on the quality of scenic roads. This could include establishing a minimum undisturbed buffer on scenic roads based on the characteristics of existing development. The Town should hold a public hearing for any scenic road proposed to be paved.

 

TABLE 14 - Designated Scenic roads in Mont Vernon

Old Milford Road from Purgatory to Jennison

Brook Road from New Boston Road to Tater Street

Old Amherst Road from Main Street to the Amherst Town Line

Old Wilton Road from Main Street to the Milford Town Line

Purgatory Road from four corners on Route 13 to Purgatory Hill

Upton Road from from Old Wilton Road

Remington Road off Kendall Hill Road

Source: Mont Vernon Town Hall

 

h. Potential Threats to Natural Resources

Most aspects of land use and development stress a community’s natural resources. Proper land management and development practices, however, can be utilized to minimize the impacts. Potential point and non-point sources of pollution in Mont Vernon are summarized below.

1. Road Salt

Road salt storage and application create the potential for sodium, calcium, and chloride contamination of surface and ground waters. Elevated sodium and chloride levels in drinking water supplies can pose serious health threats for certain population groups as well as animals and plants. In addition, high levels of chloride in surface waters can inhibit water mixing, cause stratification and salination of the bottom layers. The town stores salt in a covered facility located on Mason Road. The town does not have an established sand/salt mixture policy; however, the percentage does vary depending on the type of storm. A number of towns in the region have adopted reduced and/or no-salt programs in sensitive areas such as near public water supply wells, concentrations of individual wells and surface waters.

2. Subsurface Waste Disposal

Septic system failures from improper design, siting, or maintenance allow nutrient-rich effluent, particularly nitrogen and phosphorous, to leach into surface and ground waters. Excessive nutrient levels in surface waters create optimal conditions for growth of aquatic vegetation, which in turn, decreases levels of oxygen available for fish, impedes sunlight penetration, and clogs waterways. Contamination can also result from high levels of bacteria contained in the effluent.

The entire Town of Mont Vernon relies on subsurface waste disposal. However 41.6% of the soils that receive the highest rating for septic systems have already been developed. Great care needs to be taken in designing and siting septic systems because future development will take place on more marginal soils. The Zoning Ordinance currently specifies that no sewage disposal area shall be constructed or maintained less than seventy-five (75) from the edge of a public water body, wetlands, and wells.

3. Nutrients

Nutrients, particularly nitrogen and phosphorous, pose potential threats to surface waters. The addition of nutrients to surface waters can cause an increase in the growth of algae and other aquatic vegetation. The increase in vegetation inhibits light penetration, while decomposition of the vegetation decreases the amount of oxygen available to fish and other aquatic species.

One source of nutrients is agricultural runoff. Fertilizers applied to crops and nutrients from animal wastes contained in runoff can enter water bodies. Increased awareness of the environmental impacts and economic savings has decreased the nutrient problems associated with agricultural uses. Residential development, however, is an increasing source of nutrient runoff. Fertilizers applied to individual lawns and gardens at improper rates and times can have significant cumulative impact on nutrient levels in a water body.

The implementation of an educational program for homeowners and hobby farms regarding the use of fertilizers and the importance of buffers around water bodies is recommended.

4. Pesticides

Pesticides can have dramatic and lasting impacts on the natural and human environment. Some impacts are readily apparent. The effect of other pesticides, such as DDT (outlawed 30 years ago), which accumulates as it progresses up the food chain, may only be evidenced over a longer period of time. As with nutrients, the amount and timing of pesticide application can have a significant impact on pesticides contained in runoff. Proper application of pesticides and the use of Integrated Pest Management can reduce the potential negative impacts to a negligible level; however, the long-term impact of pesticide residues retained in the soil and released into the groundwater has yet to be determined.

The implementation of an educational program for homeowners and hobby farms regarding the use of fertilizers and the importance of buffers around water bodies is recommended.

 

6. Stormwater Runoff

Runoff from roads, parking lots and other impervious surfaces carries with it road salt, motor fuel, oil, anti-freeze, sediments, and other chemicals deposited on the surface. These chemicals pose a serious threat to surface and groundwater. The problems associated with urban runoff can be minimized by requiring drainage plans for subdivisions and site plans, and ensuring that the plans are properly supervised and executed.

7. Underground Storage Tanks

Although the NHDES inventory of potential groundwater contamination sites is not numerous, leaks in underground storage tanks (USTs) are difficult to detect and can go unnoticed for a long period of time while causing extensive contamination of water resources. See Map. A small amount of a petroleum-based product can contaminate thousands of gallons of water. UST facilities where the cumulative storage capacity is equal to or greater than 1,100 gallons are regulated by the DES-WSPCD. Facilities with a storage capacity less than 1,100 gallons, oil transmission and oil-production facilities, motor fuel and heating oil tanks for on-site residential consumption and tanks storing non-petroleum based chemicals are not regulated by the State at this time. Given the agricultural history of Mont Vernon, abandoned USTs may exist on many old farms, unknown to present owners.

The Master Plan Committee recommends setting up a survey for all known underground storage tanks in Mont Vernon and maintaining a data base of USTs that include, at the least, type, size, date of installation, predicted life and record all new USTs in the database.

8. Hazardous Waste Sites

The Town of Mont Vernon does have one hazardous waste site on Beech Hill Road. The approximately 20-acre site is mostly wooded with the exception of an approximate 2-acre cleared area in the central portion which has been historically used for waste disposal and staging of various construction and demolition debris. The containerized wastes were inventoried and removed along with approximately 15 cubic yards of contaninated soil. Groundwater wells were installed throuhgout the 2-acre area and downgradient of the site. A complete report is expected in the Fall of 2000. The Board of Selectmen continues to monitor the situation and search for funds to complete the cleanup. This experience has increased the awareness of municipal officials and residents to the contamination threats to groundwater resources and the costs associated with clean up. The site is the only identified hazardous waste site in Mont Vernon; however, other sites may exist that have yet to be identified.

9. Erosion and Sedimentation

Erosion potential increases when the soil is exposed to the elements through agriculture, silviculture, and construction activities. During land conversions, much of the protective vegetative cover is stripped from the site resulting in an increase in the velocity and volume of runoff. Soil particles are carried by surface runoff into streams, ponds, and wetlands. Sediments increase the turbidity of the water, impede light penetration and cause siltation of the waterway. Erosion and sedimentation control plans need to be required as part of the subdivision and site plan review regulations to control these negative impacts. Control methods range from simply retaining the natural vegetative cover to constructing complex drainage systems.

#245B-3