The resources are this page provide examples of how to plan for LID, including important site design considerations. Comprehensive inventory and assessment of on-site and adjacent off-site conditions are important first steps for designing and implementing an LID project.


The Department of Ecology is responsible for maintaining and enforcing LID regulations in Washington State. Please visit their website for more information.

Amending Codes
During the planning process, sometimes codes need to be updated to better reflect new information about LID, geological conditions of the site, or other data has shown that the old way of installing LID will not work. In these cases, it is necessary to amend codes to allow for the best LID installation possible on your site.

Online Tools


The power of modeling lays in the ability to ask "What if?" while doing next to nothing to the LID installation site. Asking this question allows us to see what would happen under different conditions, such as drought and flood, at very little cost and to test any scenario at any time of the year.

Site Design

There are many issues to consider when installing and LID project. For more information on the different types of LID available to you, please visit the Types of LID webpage.

Characterization; What am I building on?

LID Site Design Manuals

Site Considerations
          Web Soil Survey
          Washington Public Utility District
          Washington State Department of Natural Resources Division of Geology and Earth
          Geologic Map of the State of Washington from the USGS
          LID in Arid or Cold Climates
Water and Hydrology
          USGS Washington Water Science Center

Pan Evaporation Statistics

Pan evaporation is a measurement that combines the effects of several climate elements: temperature, humidity, rain fall, sunlight, wind, and other factors. Evaporation is greatest on hot, windy, dry, sunny days; and is greatly reduced when clouds block the sun and when air is cool, calm, and humid. Pan evaporation measurements enable farmers and ranchers to understand how much water their crops will need.

Pan  evaporation might be used in LID as a way to determine how water evaporates from an area. It can be used along with infiltration rates or soils and evapotranspiration rates of trees and other vegetation.

View the pan evaporation rates for a select series of states here.

Case Studies

2012 Stormwater Management Manual for Western Washington
Evaluate Minimum Requirement #5: Onsite Stormwater Management for a 10 Acre Single Family Subdivision (PDF)

Using Rainwater Harvesting to Enhance Low impact Development and Green Infrastructure Design
A collection of case studies that demonstrate how rainwater harvesting contributes to LID/GI design from Contech Engineered Solutions (PDF).

For more Information on the different Common LID Practices, please visit the Common LID Practices webpage.