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Surface Water Protection Measures
The following information was adapted from "Watershed Resource Papers" developed for the Dowagiac River Watershed Project by Langworthy, Strader, LeBlanc, & Associates, Inc.

One method of effectively protecting water quality is to adopt effective land development regulations for the zoning ordinance. These regulations may affect not only development projects with larger land areas and high intensity uses, but development occurring on individual lots as well.
Density Reductions
Site Plan Review Standards
Stormwater Management
Open Space Development
Lot Coverage
Parking Requirements
Waterbody Setbacks
Vegetative Buffers

Density Reductions

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Protecting water quality can mean that communities consider how much land they have planned and zoned for various uses.

Can the expected community or regional population support the planned commercial areas?
Did the planned areas for growth consider environmental limitations, such as the capacity of the soils to accommodate individual septic systems? Was the presence and efficient use of existing or planned infrastructure considered, particularly public water and sewer services?
Can existing infrastructure support planned residential, commercial, and industrial areas?
What effects will this development have on a community's natural resources?

One direct effect of land use planning is its effect on runoff and water quality. Typically development equates to impervious surface which equates to changes in the functioning of a watershed

Site Plan Review Standards

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To protect water quality and hydrology in the Watershed, it is essential to properly manage stormwater on newly developed sites. Site-level stormwater management plans can be required as part of a community's site plan review standards. Site-level stormwater management plans are generally composed of maps and a narrative. The maps and associated construction drawings show existing site features and proposed alterations highlighting the location and type of proposed stormwater management system. The narrative consists of a written statement explaining the natural and proposed drainage system, a detailed description of projected runoff quantity and quality and an explanation of why certain management practices were chosen for pollution control. Highlighted should be a detailed description of the relationship of the proposed development to drainage and runoff within the entire watershed (within reference to a watershed management plan should one exist). Provisions for site safety and maintenance of approved management measures should also be included.

Stormwater Management

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To protect water quality and hydrology in a watershed, it is essential to properly manage stormwater on newly developed sites. Site-level stormwater management plans can be required as part of a community's site plan review standards. Site-level stormwater management plans are generally composed of maps and a narrative. The maps and associated construction drawings show existing site features and proposed alterations highlighting the location and type of proposed stormwater management system. The narrative consists of a written statement explaining the natural and proposed drainage system, a detailed description of projected runoff quantity and quality and an explanation of why certain management practices were chosen for pollution control. Highlighted should be a detailed description of the relationship of the proposed development to drainage and runoff within the entire watershed (within reference to a watershed management plan should one exist). Provisions for site safety and maintenance of approved management measures should also be included.

Following is a list of guidelines that applicants should address when designing a stormwater management plan. By having a set of guidelines that clearly state the key management principles that a planning commission wants each applicant to address in a site plan, the overall consistency of site-by-site evaluation can be greatly improved.

The Storm Management System shall:
1. Consider the total environmental impact of the proposed system.
2. Consider water quality as well as water quantity.
3. Be consistent with the local Plan of Development, and any existing watershed management plan.
4. Coordinate with erosion control measures and aquifer protection.
5. Minimize disturbance of natural grades and vegetation, and utilize existing topography for natural drainage systems.
6. Preserve natural vegetated buffers along water resources and wetlands.
7. Minimize impervious surfaces and maximize infiltration* of cleansed runoff to appropriate soils.
8. Direct runoff to minimize off-site volume.
9. Reduce peak flow to minimize the likelihood of soil erosion, stream channel instability, flooding and habitat destruction.
10. Use wetlands and water bodies to receive or treat runoff only when it is assured that these natural systems will not be overloaded or degraded.
11. Provide a maintenance schedule for management practices, including designation of maintenance responsibilities

* This is very important in the Dowagiac River Watershed to maintain the existing hydrology. The Dowagiac River is eighty to ninety percent fed by groundwater, with only 10% coming from overland surface runoff.

Source: University of Connecticut Cooperative Extension System, 1995

Open Space Development

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There could be further incentives for the clustering of residential units, also known as Open Space Development. Under this development technique the allowable density is based on a "parallel plan" showing reasonable and permissible development under existing zoning. While Open Space Development may increase the net density for a smaller area of a larger parcel, the overall density would still fall into the requirements of the existing zoning.

It would also allow for the preservation of significant natural features, provide open space for recreation, or allow the continuation of farming on interior land areas. To preserve the roadside character, some or all of the required open space could be placed abutting the roadway.

One of the reasons that many buyers are looking in the rural areas is to avoid being too near other homes. Open space development is more common in areas where land prices are higher, and less common in parts of the state where land prices are very reasonable.

However, there is a segment of the marketplace that can appreciate the value of preserving larger open spaces within a development. Therefore, offering of incentives to developers for using this development technique is appropriate. The basic incentive to which developers will most readily respond is an increase in the number of units which could be permitted over the base density calculated under the parallel plan. This is generally considered a development "bonus."

The amount of the bonus may vary depending on the nature of the development, and they may be used in combinations of one or more different incentives. As an example, incentives may include an increase in the number of units if:

additional open space is provided, beyond that normally gained in the lowering of individual lot sizes;
a community wastewater and/or domestic water system is used (avoiding the need for septic systems and individual wells);
recreational amenities are provided, such as tennis courts, club house, or other similar facility;
walkways, trails, or bike paths are included within the development; and/or
significant areas of active agricultural lands are preserved.

Another incentive, where appropriate, would permit commercial uses, usually subject to certain restrictions to limit size and effect on the area.

Lot Coverage

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A variety of means exist to control the amount of impervious surfaces, but perhaps the most effective is to control lot coverages. Typically, lot coverage requirements relate only to zoning controls related to "bulk" or amount of land covered by structures, including main and accessory buildings. Additional impervious surface controls can be included to expand the definition of lot coverage to include all impervious surfaces. This definition would be:

"The part or percent of the lot occupied by impervious surfaces, including, but not limited to, buildings or structures, paving, drives, patios, and decks."

This would require an evaluation of existing lot coverage limitations, which would likely have to be increased for most districts to account for the inclusion of other surfaces in the calculation of total limits. However, this would prevent the overbuilding of some sites and help reduce the overall amount of stormwater runoff.

Parking Requirements

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Another possible change to the zoning requirements is gaining acceptance in areas where runoff is a particular concern. Most parking requirements address "minimum" numbers of spaces, but permit any size parking area to be constructed. Some communities are now utilizing a concept of "maximum" parking requirements to ensure that parking lots are not overbuilt. Generally, the maximum requirements can not be exceeded without specific justification by the developer.

There are several implications to this method of enforcing parking requirements, including the possibility of requiring some parking areas to be removed when changes of use occur that would require a lower maximum parking requirement than the previous use.

Another possible change to the zoning requirements is gaining acceptance in areas where runoff is a particular concern. Most parking requirements address "minimum" numbers of spaces, but permit any size parking area to be constructed. Some communities are now utilizing a concept of "maximum" parking requirements to ensure that parking lots are not overbuilt. Generally, the maximum requirements can not be exceeded without specific justification by the developer.

There are several implications to this method of enforcing parking requirements, including the possibility of requiring some parking areas to be removed when changes of use occur that would require a lower maximum parking requirement than the previous use.

Model Development Principles Related to Parking Requirements
- The required parking ratio governing a particular land use or activity should be enforced as both a maximum and a minimum in order to curb excess parking space construction. Existing parking ratios should be reviewed for conformance taking into account local and national experience to see if lower ratios are warranted and feasible.
- Reduce the overall imperviousness associated with parking lots by providing compact car spaces, minimizing stall dimensions, incorporating efficient parking lanes, and using pervious materials in spillover parking areas.
- Provide meaningful incentives to encourage structured and shared parking to make it more economically viable.
- Wherever possible, provide stormwater treatment for parking lot runoff using bioretention areas, filter strips, and/or other practices that can be integrated into required landscaping areas and traffic islands.

Better Site Design: A Handbook for Changing Development Rules in Your Community
Center for Watershed Protection

Waterbody Setbacks

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In proximity to water features, construction and other activities can decrease water quality through soil erosion and removal of filtering vegetation. Buffer zones around surface water features where vegetation removal or soil disturbance is minimized can help maintain water quality.

Setbacks from inland lakes and streams can be established through the zoning ordinance. Regulations may specify a minimum 100-foot setback for structures and septic systems from the shoreline. Setbacks will generally mirror the minimum requirements of the Natural Rivers Act, which provides a basis for setbacks.

Vegetative Buffers

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Setback requirements may include the preservation of at least a 25-foot wide native, uncleared vegetation buffer strip immediately adjacent to the shoreline. Boat storage and dock facilities may also be regulated. Some communities also enforce similar setbacks for agricultural operations and livestock management.
Greenbelts or vegetated buffers are an effective way to address soil erosion and the effects of runoff on surface water quality. The attraction of surface water for residential or other land uses often leads to the desire for additional views to the water by clearing vegetation along streambanks and lake shorelines. This contributes to reduced water quality and may lead to the eventual loss of aesthetic value.

Buffer Widths

In general, smaller buffers may be adequate when the buffer is in good condition (e.g. dense native vegetation, undisturbed soils), when the water body or resource is of low functional value (highly disturbed, invaded by non-native species such as purple loosestrife), and the adjacent land use has low impact potential (park land or very low density residential development). Larger buffers will provide water quality protection for high impact land uses such as highly developed commercial areas dominated by large parking lots (highly impervious surfaces).
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