(A) Low impact development (LID) is a planning and design approach to site development that is gaining popularity throughout the Commonwealth of Kentucky. Its attractiveness lies in its potential to lessen on-site and off-site stormwater impacts, reduce infrastructure costs to developers and municipalities, and promote development that is "softer on the land" compared with typical traditional development. This approach, which is applicable to residential, commercial and industrial projects, and scalable to urban, suburban and rural settings, often is linked with efforts by citizens and municipalities to foster more sustainable, livable communities.
(B) Low impact development mimics pre-development hydrology, treats stormwater as close to its source as possible, provides opportunities for groundwater recharge, preserves natural drainage systems and open space, and incorporates small-scale controls that replicate natural processes in detaining and filtering stormwater. Low impact development uses the divide and conquer theory to treat relatively small amounts of stormwater and utilize it in beneficial ways. This contrasts with conventional stormwater management approaches geared to concentrating and collecting runoff and exporting it off-site as a waste product.
(C) Low impact development techniques provide many benefits to a wide variety of stakeholders. Municipalities can often increase collaborative public/private partnerships and potentially reduce the cost of municipal infrastructure and maintenance (streets, curbs, gutters, and storm sewers). Municipalities may also reduce or eliminate nonpoint source pollutants from reaching waterways. The reduction of stream bank erosion protects regional flora and fauna. Balancing growth needs with environmental protection can potentially enhance both physical health (by increasing opportunities to walk and exercise outside) and mental health (by improving the visual quality of the environment which can reduce stress and mental fatigue).
(D) Developers can potentially reduce the costs of clearing and grading land, infrastructure (streets, curbs, and gutters), storm water management, and impact fees. They also can potentially increase lot yield and marketability. Low impact development potentially protects the environment by preserving the integrity of ecological and biological systems. Preservation of trees and natural vegetation reduces impacts to plants and animals. Water quality is improved when sediment, nutrient, and toxic loads to water bodies are reduced.
(1) Green infrastructure is an approach to stormwater management that integrates systems that mimic natural processes in order to infiltrate, evaporate, and/or reuse stormwater. Green infrastructure uses soils, topography, and vegetation in a way that minimizes the impact of human disturbance and maintains the pre-development hydrology and water quality of urban environments. The goal of green infrastructure is to design a built environment that functions as part of an ecosystem rather than apart from it. This is an innovative approach to urban stormwater management that strategically integrates stormwater controls throughout the urban landscape and does not rely solely on conventional end-of-pipe structural practices.
(2) Green infrastructure practices have the potential to address one or more of the following stormwater related issues: reduce runoff volume, reduce peak discharge, and improve water quality. A site may contain several green infrastructure practices that work together to capture, infiltrate and/or harvest rain water. The following section describes nine of the most common green infrastructure practices divided into three categories: capture, infiltration and harvest/reuse. Each green infrastructure practice has its advantages and appropriate applications. This section assesses those and describes each practice in terms of suitability, limitations, land area demands, relative costs, and maintenance.
(a) Capture.
1. Permeable pavement is available in the form of pervious concrete, porous asphalt, permeable pavers (concrete and brick).
2. Vegetative roofs/vegetative walls are separated into two types based on the depth of growing media: extensive (2"-6") and intensive (6"-4').
3. Tree box filters have mini filtration areas beneath trees or shrubs and are contained within an in-ground unit.
(b) Infiltration.
1. Downspout disconnection directs rain water away from buildings and allows it to flow over permeable surfaces such as grass.
2. Vegetative swales are planted with grasses or native plantings designed to accept rain water flow then allow it to infiltrate the ground and be filtered.
3. Rain gardens and bio-retention areas are amended with soils that allow rainwater infiltration. They are planted with native grasses and wildflowers that move water from the soil into the air through evapotranspiration.
4. Street trees reduce storm water runoff and heat island effects through evapotranspiration.
(c) Harvesting/reuse.
1. Rain barrels and cisterns are appropriate for residential, commercial and industrial sites. Rainwater reuse includes irrigation for lawns, planting beds, and nonportable water uses.
2. Underground storm water storage systems can be used to meet storm water detention requirements.
(d) Incentives.
1. Incentives to implement green infrastructure practices potentially include the following: reduction of infrastructure costs for storm water management, increase in development marketability, reduction in land clearing and grading costs, potential synergies for meeting storm water quality, quantity and landscape requirements for the City of Winchester and the county.
2. The EPA has produced two green infrastructure reports entitled “Green Infrastructure Case Studies: Municipal Policies for Managing Stormwater with Green Infrastructure” August, 2010, and “Reducing Stormwater Cost through Low Impact Development (LID) Strategies and Practices” December, 2007. These highlight case studies from across the United States that demonstrate the benefits of green infrastructure practices.
(c) Resources.
(Ord. passed 3- -1995; Ord. passed 10- -2005; Ord. 2018-03, passed 2-14-2018; Ord. passed 1- -2020)