Low Impact Development and Green Infrastructure

The term low impact development (LID) refers to best management practices that use or mimic natural processes that result in the infiltration, evapotranspiration or use of stormwater in order to protect water quality and associated aquatic habitat (US EPA). LID works with nature to manage stormwater as close to its source as possible and includes landscapes features such as bioretention facilities, rain gardens, vegetated rooftops, rain barrels and permeable pavements.

Green infrastructure uses vegetation, soils, and other elements and practices to restore some of the natural processes required to manage water and create healthier urban environments. At the city or county scale, green infrastructure is a patchwork of natural areas that provides habitat, flood protection, cleaner air, and cleaner water. At the neighborhood or site scale, stormwater management systems that mimic nature soak up and store water (US EPA). Green Infrastructure can also refer to the watershed scale landscapes that manage rainfall, such as wetlands, riparian corridors, forests, pastures, prairies and more.

By implementing LID principles and practices, and restoring and/or preserving green infrastructure, water can be managed in a way that reduces the impact of built areas and promotes the natural movement of water within an ecosystem or watershed.

RFP for Green Infrastructure Design Services

The Beaver Watershed Alliance is requesting proposals from qualified consulting firms interested in providing geotechnical engineering, civil engineering, land surveying and landscape architecture services for the Implementing Green Infrastructure Elements for Enhanced Water Quality in the Beaver Lake Watershed grant project.

To be considered, proposals shall be received at the Beaver Watershed Alliance offices, located at 614 E. Emma Avenue, Suite M438, Springdale, Arkansas, Friday, August 31, 2018 prior to 2:00:00 PM, local time. No late submittals will be accepted. Submittals will not be accepted at a later date.

Forms and addendums can be downloaded, please see links below. All questions regarding the process should be directed to Becky Roark at becky@beaverwatershedalliance.org or (479) 750-8007.

Proposals submitted shall be from firms that are qualified to do business and licensed in accordance with all applicable laws of the state and local governments where the projects are located.

Pursuant to Arkansas Code Annotated §22-9-203, the Beaver Watershed Alliance encourages all qualified small, minority and women business enterprises to bid on and receive contracts for goods, services, and construction. Also, the Beaver Watershed Alliance encourages all general contractors to subcontract portions of their contract to qualified small, minority and women business enterprises.

The Beaver Watershed Alliance reserves the right to reject any or all proposals and to waive irregularities therein, and all Proposers shall agree that such rejection shall be without liability on the part of the Beaver Watershed Alliance for any damage or claim brought by any Proposer because of such rejections, nor shall the Proposers seek any recourse of any kind against the Beaver Watershed Alliance because of such rejections. The filing of any Proposal in response to this invitation shall constitute an agreement of the Proposer to these conditions.

RFP Announcement
Full RFP
Press Release for Green Infrastructure Project

Low Impact Development Mini-Grant Program

Each year, the Beaver Watershed Alliance provides financial assistance for landowners who want to install low impact development features on their property through the Low Impact Development (LID) Mini-Grant Program.

The LID Mini-Grant Program continues to assist property owners, businesses, schools, cities, churches and other public spaces to implement landscape features to improve water quality for the Beaver Lake watershed. Applications are taken throughout the year and will be reviewed as they are received. Beaver Watershed Alliance offers technical assistance to help select a location, conceptual design and can recommend management techniques for LID features.

If you are interested in installing LID on your property, please contact us at 479-750-8007 or info@beaverwatershedalliance.org to find out more information or check for updates on program details.

Download Low Impact Development Mini Grant Application
Download Rain Garden Fact Sheet
Download Ozark Native Plants Fact Sheet

Low Impact Development Features

Rain Gardens

LID Rain Garden

A rain garden is a landscaped area designed to capture and hold excess rain water runoff from impervious areas for a short period, allowing it to soak into the soil. Rain gardens help to slow the flow of water discharged from impervious surfaces during and after precipitation events, reducing water pollution and flooding and allowing groundwater recharge. Other benefits include aesthetics and wildlife habitat creation within a rain garden. Rain gardens typically aren't more than 500 square feet and are great to use near downspouts on home properties, businesses, churches, schools or other areas that you want to treat a smaller impervious area.

Learn More

US Environmental Protection Agency
Green Infrastructure
Low Impact Development

Arkansas Natural Resources Commission
Water Development, Management, Conservation

Arkansas Natural Resources Commission
Download Manual


LID Bioswales

Like a rain garden, bioswales use native vegetation to slow down, filter and soak in rainfall, but instead of ponding the rain, bioswales channel rain from one point to another, and release the filtered water to another point. These applications are great along areas between two homes (think dry creek bed), along parking lot perimeters, and medians.

Pervious Pavers

LID Pervious Pavers

Technologies continue to develop to design paving systems that allow water to soak into the ground, rather than adding impermeable surfaces that generate more runoff. Pervious pave systems typically consist of solid blocks/pavers that fit together but have void space in joints that allow water to soak in. Beneath the surface, a layer of smaller stones create a detention basin to hold water and allow it to soak in slowly into the ground. Underdrains are typically used in this layer to connect to pipes or release water in the event of an overflow. Pervious pavers are an excellent alternative to concrete or asphalt, come in other forms such as grid and grass systems or crushed granite, can be easier to maintain and generally have a longer life-span versus asphalt, saving money on the investment over time.

Rain Harvesting

LID Rain Harvesting Cistern

NWA receives over 48" of rainfall annually, and a 1" rain storm will generate 617 gallons of runoff from a 1,000 square foot roof or parking lot. Add that to runoff from surrounding landscapes, such as driveways and compacted lawns, and hundreds of thousands of gallons of water can runoff your property. Capturing this free resource can help reduce rain runoff into nearby streams, can provide a resource for irrigation and outdoor watering needs, and can reduce water utility bills. We recommend larger cistern systems, that would have the capacity to hold the amount of rainfall we receive, or, there are plans available online to connect the 50-gallon barrels if you want to save money on costs!

Green Roofs

LID Green Roof

A green roof system is an extension of the existing roof which involves, at a minimum, high quality water-proofing, root repellent system, drainage system, filter cloth, a lightweight growing medium, and plants. Green roof systems may be modular, with drainage layers, filter cloth, growing media, and plants already prepared in movable, often interlocking grids, or loose laid/built-up whereby each component of the system may be installed separately. Green roof development involves the creation of "contained" green space on top of a human-made structure. Benefits include reducing temperatures at least 10 degrees underneath (also reducing the heat-island effect), reducing rain runoff entering downspouts from roof areas, and filtering rain through vegetated systems.

Soil Amendments

LID Soils

When you install LID features, such as rain gardens and bioswales, it may be necessary to use amended soils to help drain the water more adequately. A soil test should always be done prior to installing these features to determine if soil amendments are needed. Your local county extension service will conduct free soil analysis for homeowners. When you have heavy clay soils, water will not soak in as easily, thus the need for "fluffier" soils that can handle inundation better. Typical soil amendments include equal parts of compost, builder's grade sand and clay. Many local nurseries offer a pre-mixed soil amendment.

Native Plants

LID Native Plants

Selecting the right plant for the right place can ensure that your landscape thrives. Why native plants? Plants that are adapted to our region are more resilient to our climate and can withstand the drought and rainfall patterns, are more resistant to disease, are beneficial to wildlife by providing food, cover and habitat, can save money and management time, as well as protect our most precious natural resource, water, by providing ecosystem services. Through a process called phytoremediation, native plants use natural biological, chemical or physical activities and processes of the plants that can take up nutrients or contaminants. Plants are unique organisms equipped with remarkable metabolic and absorption capabilities, as well as transport systems to clean and filter rain runoff.

Managing LID

LID Management

Communities contemplating "green" LID approaches may be concerned that maintenance costs will grow as a result of switching from traditional "grey" stormwater practices. While this may be true in some cases, in general, LID practices have lower long-term lifecycles costs, perform better, and provide additional benefits such as improved aesthetics and enhanced property values. In contrast, LID practices typically require a lower initial investment and more ongoing maintenance - especially in the early years as vegetation becomes established in bioretention areas. Once established, LID practices can often be maintained in the same manner as other landscaping elements that require mowing, weeding and debris removal. Note that permeable pavements require frequent vacuum sweeping to maintain water quality benefits but can still result in cost savings by avoiding the land space and costs needed to build ponds. For homeowner applications, rain gardens and bioswales will require weeding until plants mature and establish, watering for the first 1-2 seasons, and rain cisterns will require winterizing and occasional downspout cleaning. There are many great resources online for managing LID features at both the homeowner scale and larger community scale. BWA offers many educational opportunities to come and learn about maintaining LID landscapes, check our calendar for ways to come and learn!