Low Impact Development

The Low Impact Development Seminar held on April 25, 2012 was attended by over 100 professionals.  Thank you for your participation.  The following guest speakers graciously gave permission to post their LID presentations:

Thomas Ballestero, PE, PhD, PH, CGWP, PG:
Stormwater Management Strategies for Reduction of Nitrogen and Phosphorus Loading to Surface Waters

Fred Cowett:
Trees and Stormwater

Steve Trinkaus, PE, CPESC, CPSWQ:
Hydrologic Benefits of Vegetation in Site Design

Mark Swinton, PhD:
How Development Influences Stream Discharge and Loadings & Climate Change: What to Expect

Jeremiah Bergstrom, LLA, ASLA
Functional Landscapes for Stormwater Management

Larry Coffman - Keynote Speaker:
Lake George / Low Impact Development Ecosystems Based Solutions

Olga Vargas and Bob Kort:
Impacts of Land Use and Development Activities in Soils  

Shirley Clark, PhD, PE, DWRE:
Soils, Development and Stormwater

Paul Mankiewicz, PhD:
Gaia Soil - Alternative Soils Mixture

Steve Trinkaus, PE, CPESC, CPSWQ:
Water Quality and Quantity Impacts of Impervious Cover

Implement Low Impact Development Design Strategies

Deb Caraco, PE:
The Runoff Reduction Method

John Dunkle, PE:
Reducing Runoff with Green Infrastructure

Jenna Calvi:
Green Infrastructure and Low Impact Development

Low Impact Development Project Launched to Improve Design and Building Practices for Stormwater Management

"The majority of phosphorous loading (to Lake George) is from surface water runoff, with a disproportionate amount of the runoff derived from developed areas around the lake as compared to undeveloped (forested or agricultural) areas. Although developed areas only account for 5 percent of the land area in the watershed, they produce 43 percent of all the phosphorous that enters the lake as surface runoff."
Excerpt from: "Total Phosphorous Budget Analysis - Lake George Watershed
New York - October 2001"

The Lake George WATERKEEPER has begun a Low Impact Development Project to reach out to developers, builders, architects, engineers, realtors, and other development practitioners around Lake George in order to improve management and control of stormwater. Too often stormwater controls are not fully developed and inadequate technologies are used. Stormwater is one of the biggest long-term threats to the water quality of Lake George.

There is documented evidence that development is contributing to the aging of Lake George through the increase of nutrients, particularly phosphorous. Aging of lakes refers to nutrient enrichment of the waters increasing aquatic plant productivity, particularly algae growth. The alteration of the landscape from mature forest to impervious surfaces (pavement and roofs) or turf lawns increases the amount of runoff. This change in ground cover not only increases runoff because of the inability for infiltration, but reduces the potential for the removal of nutrients through adsorption to roots and soil materials as well as the natural biological treatment.

But this is not the only manner that alteration of natural landscape has on increasing surface runoff and subsequent increases in nutrient levels to the Lake. Natural depressions provide areas for attenuation of stormwater, reducing runoff and promoting infiltration. Changing existing grades removes these depressions, which increases runoff. Removal of mature, deeper rooted vegetation and the excavation of soils to accommodate building sites increases runoff by decreasing the time of concentration and reduction in the flowpath.

Low impact development (LID) is a relatively new stormwater management design technology that is intended to mimic the natural hydrologic cycle in order to reduce runoff rates and the subsequent increases in nutrients and pollutants. Low impact development incorporates objectives such as:

• Minimizing disturbance
• Increasing hydrologic disconnects (by decreasing connected impervious coverage)
• Increasing drainage flow paths
• Increasing infiltration opportunities
• Reducing impervious coverage
• Preserving and recreating natural landscape features

Stormwater management regulations have been in effect in the Lake George watershed for ten years. These regulations are based on good concepts for the reduction of post-development runoff. However, research over the past several years has led to improved treatment methods, which greatly increases the capability of stormwater management and treatment.

Low Impact Development is not just the implementation of technology, but it is a change in the design approach and attitude towards stormwater. Stormwater should not be viewed as a waste product which needs to be disposed of, but should be incorporated into the natural design processes. Stormwater management needs to be evaluated with the initial phases of the site design and planning process. There should be a focus on the prevention of stormwater runoff instead of the mitigation of stormwater. Stormwater should be managed as close to the source as possible and should rely on small scale treatment practices in lieu of end-of-the-pipe solutions.

Low impact development is new techniques and design standards. As with most new standards, there is concern that there will be an increase in cost for construction. Low impact development has been documented to reduce the cost to a developer. This is accomplished through the reduction of pavement lengths and widths, the use of grass and vegetated swales instead of curb, gutter and piping, and placing natural control measures closer to the source, therefore reducing the size and quantity of structures.

It is the hope of the Lake George Waterkeeper that these design standards can be implemented into the design mentality that is utilized for projects within the Lake George watershed. These measures will add value to projects as well as enhance the functionality of all aspects of a project including the connectedness to open space, retaining of existing landscape features and soils, and overall improvement of quality of life.