5.5 RIVERFRONT AREA
Riverfront areas are likely to be significant to: public or private water supply, ground water supply, flood control, storm damage prevention, prevention of pollution, the protection of fisheries, wildlife and/or rare species habitat, water quality control, water pollution control, protection of land containing shellfish, and erosion and sedimentation control.
Land adjacent to rivers and streams can protect the natural integrity of these water bodies. The presence of natural vegetation within riverfront areas is critical to sustaining rivers as ecosystems and providing these public values.
The riverfront area can prevent degradation of water quality by filtering sediments, toxic substances (such as heavy metals), and nutrients (such as phosphorus and nitrogen) from stormwater, nonpoint pollution sources, and the river itself. Sediments are trapped by vegetation before reaching the river. Nutrients and toxic substances may be detained in plant root systems or broken down by soil bacteria. Riverfront areas can trap and remove disease-causing bacteria that otherwise would reach rivers and coastal estuaries where they can contaminate shellfish beds and prohibit safe human consumption. Natural vegetation within the riverfront area also maintains water quality for fish and wildlife.
Where rivers serve as water supplies or provide induced recharge to wells, the riverfront area can be
important to the maintenance of drinking water quality and quantity. Land along rivers in its natural state
with a high infiltration capacity increases the yield of a water supply well. When riverfront areas lack the
capacity to filter pollutants, contaminants can reach human populations served by wells near rivers or by
direct river intakes. The capacity of riverfront areas to filter pollutants is equally critical to surface water
supplies, reducing or eliminating the need for additional treatment. In the watershed, mature vegetation
within riverfront areas provides shade to moderate water temperatures and slow algal growth, which can
produce odors and taste problems in drinking water.
Within riverfront areas, surface water interaction with groundwater significantly influences the stream
ecosystem. The dynamic relationship between surface and groundwater within the “hyporheic zone”, located below the stream channel, sustains communities of aquatic organisms which regulate the flux of nutrients, biomass and the productivity of organisms including fish within the stream itself. The hyporheic zone extends to greater distances horizontally from the channel in large, higher order streams with alluvial floodplains, but the interaction within this zone is important in smaller streams as well. By providing recharge and retaining natural flood storage, as well as by slowing surface water runoff, riverfront areas can mitigate flooding and damage from storms. The root systems of riverfront vegetation keep soil porous, increasing infiltration capacity. Vegetation also removes excess water through
evaporation and transpiration. This removal of water from the soil allows for more infiltration when flooding occurs. Increases in storage of floodwaters can decrease peak discharges and reduce storm damage. Vegetated riverfronts also dissipate the energy of storm flows, reducing damage to public and private property.
Riverfront areas are critical to maintaining thriving fisheries. Maintaining vegetation along rivers promotes fish cover, increases food and oxygen availability, decreases sedimentation, and provides spawning habitat. Maintenance of water temperatures and depths is critical to many important fish species. Where groundwater recharges surface water flows, loss of recharge as a result of impervious surfaces within the riverfront area may aggravate low flow conditions and increase water temperatures. In some cases, summer stream flows are maintained almost exclusively from groundwater recharge. Small streams are most readily impacted by removal of trees and other vegetation along the shore.
Riverfront areas are important wildlife habitat, providing food, shelter, breeding, migratory, and overwintering areas. Even some predominantly upland species use and may be seasonally dependent on riverfront areas. Riverfront areas promote biological diversity by providing habitats for an unusually wide variety of upland and wetland species, including bald eagles, osprey, and kingfishers. Large dead trees provide nesting sites for bird species that typically use the same nest from year to year. Sandy areas along rivers may serve as nesting sites for turtles and water snakes. Riverfront areas provide food for species such as wood turtles which feed and nest in uplands but use rivers as resting and overwintering areas.
Riverfront areas provide corridors for the migration of wildlife for feeding or breeding. Loss of this connective function, from activities that create barriers to wildlife movement within riverfront areas, results in habitat fragmentation and causes declines in wildlife populations. Wildlife must also be able to move across riverfront areas, between uplands and the river.
Vernal pools are frequently found within depressions in riverfront areas. These pools are essential breeding sites for certain amphibians which require isolated, seasonally wet areas without predator fish. Most of these amphibians require areas of undisturbed woodlands as habitat during the non-breeding seasons. Some species require continuous woody vegetation between woodland habitat and the breeding pools. Depending on the species, during non-breeding seasons these amphibians may remain near the pools or travel one-fourth mile or more from the pools. Reptiles, especially turtles, often require areas along rivers to lay their eggs. Since amphibians and reptiles are less mobile than mammals and birds, maintaining integrity of their habitat is critical. In those portions so extensively altered by human
activity that there important wildlife habitat functions have been effectively eliminated, riverfront areas are not significant to the protection of important wildlife habitat and vernal pool habitat.
5.5.1 Definitions, Critical Characteristics and Boundaries.
A Riverfront Area is the area of land between a river’s mean annual high water line and a parallel line located 200 feet away, measured horizontally outward from the river’s mean annual high water line. The riverfront area may include or overlap other resource areas or their buffer zones. The riverfront area does have a buffer zone. Rivers begin at the point an intermittent stream becomes perennial, or at a spring or pond which discharges throughout the year. Water does not flow throughout the year in intermittent streams; when the water is not flowing, it may remain in isolated pools or surface water may be absent. Downstream of the point of perennial flow, a perennial stream normally remains a river except when interrupted by a lake or pond.
A river is any natural flowing body of water that empties to any ocean, lake, pond, or other river and which flows throughout the year. Perennial streams are rivers; intermittent streams are not rivers.
The Commission shall presume that a river or stream shown as perennial on the current United States Geologic Survey topographic quadrangle map (at 1:24,000 scale) (U.S.G.S.) or a more recent map provided by the DEP is perennial unless rebutted by evidence from a competent source asserting to the contrary or a finding by the Commission based on site visit observation. DEP staff, Conservation Commissioners, and Conservation Commission staff are competent sources; the Commission may consider evidence from other sources.
If a river or stream is shown as intermittent or not shown on the current U.S.G.S. map or a more recent map provided by the DEP, an assertion that it is perennial must be supported by evidence by the person making the assertion or by the Commission upon its own initiative, which may include evidence of the presence of aquatic macroinvertebrate species which require perennial flows; evidence of a stream order of two or greater; presence of a U.S.G.S. stream gauge at or upstream of the project location; a watershed size of greater than three square miles, or other evidence.
If a river or stream is shown as perennial on the current U.S.G.S. map or more recent map provided by the DEP, an assertion that it is intermittent must be supported by evidence by the person making the assertion which may include field observations that the river is not flowing for a minimum of 3 consecutive months for at least 2 consecutive years, provided the date of observation is not within an extended drought; absence of a channel or banks; soils information showing the groundwater elevation is not at or near the surface; or other evidence. (See section 4.22).
Rivers include the entire length of the major rivers (Assabet, Blackstone, Charles, Chicopee, Concord, Connecticut, Deerfield, Farmington, French, Hoosic, Housatonic, Ipswich, Merrimack, Millers, Nashua, Neponset, Parker (Essex County), Quinebaug, Shawsheen, Sudbury, Taunton, Ten Mile, and Westfield).
Rivers include perennial streams which are dry during periods of extended drought, defined as period when precipitation for the previous four months was below normal for the period of record, with at least three of the four months 50% or less and two of the four months 75% or less of normal precipitation. Rivers and streams which are perennial under natural conditions but affected by drawdown from withdrawals of water supply wells or direct withdrawals shall be considered perennial.
Where rivers flow through lakes or ponds, the riverfront area stops at the inlet and begins again at the outlet. A water body identified as a lake, pond, or reservoir on the current U.S.G.S. map or more recent map provided by the DEP, is a lake or pond, unless Commission determines that the water body has primarily riverine characteristics. When a water body is not identified as a lake, pond, or reservoir on the current U.S.G.S. map or more recent map provided by the DEP, the water body is a river if it has primarily riverine characteristics. Riverine characteristics include unidirectional flow that can be visually observed or measured in the field.
In addition, rivers are characterized by horizontal zonation, as opposed to the vertical stratification typically associated with lakes, ponds, and embayments. Great Ponds (i.e., any pond which contained more than ten acres in its natural state, as calculated based on the surface area of lands lying below the natural high water mark; a list is available from the DEP) are never rivers.
Mean Annual High-Water Line of a river is the line that is apparent from visible markings or changes in the character of soils or vegetation due to the prolonged presence of water and that distinguishes between predominantly aquatic and predominantly terrestrial land. Field indicators of bankfull conditions shall be used to determine the mean annual high-water line. Bankfull field indicators include but are not limited to: changes in slope, changes in vegetation, stain lines, top of pointbars, changes in bank materials, or bank undercuts.
1. In most rivers, the first observable break in slope is coincident with bankfull conditions and the mean annual high-water line.
2. In some river reaches, the mean annual high-water line is represented by bankfull field indicators that occur above the first observable break in slope, or if no observable break in slope exists, by other bankfull field indicators. These river reaches are characterized by at least two of the following features: low gradient, meanders, oxbows, histosols, a low-flow channel, or poorly-defined or nonexistent banks.
Measured horizontally means that the riverfront area extends at a right angle to the mean annual high-water line rather than along the surface of the land.
Where a river runs through a culvert more than 200 feet in length, the riverfront area stops at a perpendicular line at the upstream end of the culvert and resumes at the downstream end. When a river contains islands, the riverfront area extends landward into the island from and parallel to the mean annual high-water line.
The physical characteristics of a Riverfront Area are critical to the protection of the interests identified above.
The Boundary of the Riverfront Area is a line parallel to the mean annual high-water line, located at the
outside edge of the riverfront area. At the point where a stream becomes perennial, the riverfront area begins at a line drawn as a semicircle with a 200 radius around the point and connects to the parallel line perpendicular to the mean annual high-water line which forms the outer boundary.
5.5.2 Presumption of Significance
Where a proposed activity involves work within the riverfront area, the Commission shall presume that the area is significant to protect: the private or public water supply; groundwater; flood control; prevent storm damage; prevent pollution; land containing shellfish; wildlife and/or rare species habitat; water quality, water pollution control, erosion and sedimentation, and fisheries. The presumption is rebuttable and may be overcome by a clear showing that the riverfront area does not play a role in the protection of each one of these interests. In the event that the presumption is deemed to have been overcome as to the protection of all the interests, the issuing authority shall make a written determination to this effect, setting forth its grounds. Where the applicant provides information that the riverfront area at
the site of the activity does not play a role in the protection of a single interest, the issuing authority may determine that the presumption for that interest has been rebutted and the presumption of significance is partially overcome. The applicant must overcome, beyond reasonable doubt, each and every presumption of significance in order to conduct work within the 200 foot Riverfront Resource Area.
5.5.3 General Performance Standard
The applicant shall prove by a preponderance of the evidence that there are no practicable and substantially equivalent economic alternatives to the proposed project with less adverse effects on the interests identified and that the work, including proposed mitigation, will have no significant adverse impact on the riverfront area to protect the interests identified. In the event that the presumption is partially overcome, the issuing authority shall make a written determination setting forth its grounds in the Order of Conditions. The Commission shall impose conditions in the Order that contribute to the protection of interests for which the riverfront area is significant.
The work shall meet the performance standards for all other resource areas located within the riverfront area.
No project may be permitted within the riverfront area which will have any adverse effect on specified habitat sites of rare wetland or upland, vertebrate or invertebrate species, or which will have any adverse effect on vernal pool habitat whether certified or identified by the Commission prior to or during the public hearing.
Practicable alternatives There must be no practicable and substantially equivalent economic alternative to the proposed project with less adverse effects on the interests identified.
Definition of Practicable An alternative is practicable and substantially equivalent economically if it is available and capable of being done after taking into consideration costs, existing technology, proposed use, and logistics, in light of overall project purposes. Available and capable of being done means the alternative is obtainable and feasible. Project purposes shall be defined generally (e.g., single family home, residential subdivision, expansion of a commercial development). The alternatives analysis may reduce the scale of the activity or the number of lots available for development, consistent with the project purpose and proposed use. Transactions shall not be arranged to circumvent the intent of alternatives analysis review. The four factors to be considered are:
1. The cost of an alternative must be reasonable for the project purpose, and cannot be prohibitive. Higher or lower costs taken alone will not determine whether an alternative is practicable. An alternative for proposed work in the riverfront area must be a practicable and substantially equivalent economic. In considering the costs to the owner, the evaluation should focus on the financial capability reasonably expected from the type of owner (e.g., individual homeowner, residential developer, small business owner, large commercial or industrial developer) rather than the personal or corporate financial status of that particular owner. Applicants should not submit, nor should issuing authorities request, financial information of a confidential nature, such as income tax records or bank
statements. Issuing authorities may require documentation of costs, but may also base their determinations on descriptions of alternatives, knowledge of alternative sites, information provided by qualified professionals, comparisons to costs normally associated with similar projects, or other evidence. Any documentation of costs should be limited to that required for a determination of whether the costs are reasonable or prohibitive.
2. Existing technology, which includes best available measures (i.e., the most up-to-date technology or the best designs, measures, or engineering practices that have been developed and are commercially available);
3. The proposed use. This term is related to the concept of project purpose
4. Logistics. Logistics refers to the presence or absence of physical or legal constraints. Physical characteristics of a site may influence its development. Legal barriers include circumstances where a project cannot meet other applicable requirements to obtain the necessary permits at an alternative site. An alternative site is not practicable if special legislation or changes to municipal zoning would be required to achieve the proposed use or project purpose.
Scope of Alternatives The scope of alternatives under consideration shall be commensurate with the type and size of the project. The issuing authority shall presume that alternatives beyond the scope described below are not practicable and therefore need not be considered. The Commission or another party may overcome the presumption by demonstrating the practicability of a wider range of alternatives, based on cost, and whether the cost is reasonable or prohibitive to the owner; existing technology; proposed use; and logistics in light of the overall project purpose.
1. The area under consideration for practicable alternatives is limited to the lot for activities associated with the construction or expansion of a single family house on a lot recorded on orbefore August 1, 1996.
2. The area under consideration for practicable alternatives is limited to the lot, the subdivided
lots and any adjacent lots formerly or presently owned by the same owner on a lot recorded after August 1, 1996.
3. The area under consideration for practicable alternatives extends to the original parcel and the subdivided parcels, any adjacent parcels, and any other land which can reasonably be obtained within the municipality for adjacent lots, reasonably be obtained, means to purchase at market prices if otherwise practicable, as documented by offers (and any responses). For other land, reasonably be obtained means adequate in size to accommodate the project purpose and listed for sale within appropriately zoned areas, at the time of filing a Request for Determination or Notice of Intent, within the municipality.
4. Alternatives extend to any sites which can reasonably be obtained within the appropriate area.
Evaluation of Alternatives The applicant shall demonstrate that there are no practicable and substantially equivalent economic alternatives within the Scope of Alternatives with less adverse effects on the interests identified. The applicant shall submit information to describe sites and the work both for the proposed location and alternative site locations and configurations sufficient for a determination by the Commission. The level of detail of information shall be commensurate with the scope of the project and the practicability of alternatives. Where an applicant identifies an alternative which can be summarily demonstrated to be not practicable, an evaluation is not required.
The purpose of evaluating project alternatives is to locate activities so that impacts to the riverfront area are avoided to the extent practicable. Projects within the Scope of Alternatives must be evaluated to determine whether any are practicable. As much of a project as is feasible shall be sited outside the riverfront area. If siting of a project entirely outside the riverfront area is not practicable, the alternatives shall be evaluated to locate the project as far as possible from the river.
The Commission shall not require alternatives which result in greater or substantially equivalent adverse impacts. If an alternative would result in no identifiable difference in impact, the issuing authority shall eliminate the alternative. If there would be no less adverse effects on the interests identified, the proposed project rather than a practicable alternative shall be allowed, but the criteria for determining no significant adverse impact must still be met. If there is a practicable and substantially equivalent economic alternative with less adverse effects, the proposed work shall be denied and the applicant may either withdraw the Notice of Intent or receive an Order of Conditions for the alternative, provided the applicant submitted sufficient information on the alternative in the Notice of Intent.
No Significant Adverse Impact The work, including proposed mitigation measures, must have no significant adverse impact on the riverfront area to protect the interests.
Within 200 foot riverfront areas, the issuing authority may, in unusual circumstances, allow, as a consideration and not as a right, the alteration of up to 10% of the riverfront area within the lot, on a lot recorded on or before October 6, 1997, or up to 10% of the riverfront area within a lot recorded after October 6, 1997, provided that:
1. At a minimum, a 100 foot wide area of undisturbed vegetation is provided. This area shall extend from mean annual high-water along the river unless another location would better protect the interests identified. If there is not a 100 foot wide area of undisturbed vegetation within the riverfront area, existing vegetative cover shall be preserved or extended to the maximum extent feasible to approximate a 100 foot wide corridor of natural vegetation. Replication and compensatory storage required to meet other resource area performance standards are allowed within this area; structural stormwater management measures may be allowed only when there is no practicable alternative. Temporary impacts where necessary for installation of linear site-related utilities are allowed, provided the area is restored to
its natural conditions.
2. Stormwater is managed according to standards established by the DEP Phase II Stormwater requirements.
3. Proposed work does not impair the capacity of the riverfront area to provide important wildlife habitat functions. Work shall not result in an impairment of the capacity to provide vernal pool habitat identified by evidence from a competent source, but not yet certified. For work within an undeveloped riverfront area which exceeds 5,000 square feet, Commission requires a wildlife habitat evaluation study under 310 CMR 10.60.
4. Proposed work shall not impair groundwater or surface water quality, by incorporating erosion and sedimentation controls and other measures to attenuate nonpoint source pollution. The calculation of square footage of alteration shall exclude areas of replication or compensatory flood storage required to meet performance standards for other resource areas, or any area of restoration within the riverfront area. The calculation also shall exclude areas used for structural stormwater management measures, provided there is no practicable alternative to siting these structures within the riverfront area and provided a wildlife corridor is maintained (e.g. detention basins shall not be fenced).
When an applicant proposes restoration on-site, of degraded riverfront area, alteration may be allowed at a ratio in square feet of at least 2:1 of restored area to area of alteration not conforming to the criteria. Restoration shall include:
1. Removal of all debris, but retaining any trees or other mature vegetation;
2. Grading to a topography which reduces runoff and increases infiltration;
3. Coverage by topsoil at a depth consistent with natural conditions at the site; and
4. Seeding and planting with an erosion control seed mixture, followed by plantings of herbaceous and woody species appropriate to the site.
When an applicant proposes mitigation either on-site or in the riverfront area within the same
general area of the river basin, alteration may be allowed at a ratio in square feet of at least 2:1 of mitigation area to area of alteration for previously disturbed sites.
The following may be allowed in the Riverfront Area by the Commission and requires the filing of a Notice of Intent and prior review and approval:
1.Fencing, provided it will not constitute a barrier to wildlife movement; stonewalls; stacks ofcordwood may be allowed in the riverfront area;
2.Vista pruning, provided the activity is located more than 100 feet from the mean annual high water line within a riverfront area or from bordering vegetated wetland, whichever is farther;
3. Plantings of native species of trees, shrubs, or groundcover, but excluding turf lawns;
4. The conversion of lawn to uses accessory to existing single family houses in existence on August 7, 1996, such as decks, sheds, patios, and pools, provided the activity is located more than 50 feet from the mean annual high-water line within the riverfront area or from bordering vegetated wetland, whichever is farther, and erosion and sedimentation controls are implemented during construction;
5. The conversion of impervious to vegetated surfaces, provided erosion and sedimentation controls are implemented during construction; and
6. The repair or upgrade of existing septic systems in compliance with 310 CMR 15.000.
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