Stormwater Library
resources for stormwater professionalsArchive for Research Studies
Identifying the roadblocks to LID – 2008 Puget Sound Study
In 2008, a research study was sponsored by the State of Washington to survey the progress being made by 19 local governments in adopting LID controls into their building codes. A representative from each of the 19 municipalities was asked the same set of questions regarding the barriers seen to LID implementation. Some of the trends they found in the responses include the following:
- Perception that LID is not a proven technology
- General public and government officials lack understanding of LID
- Perception that LID is more expensive when compared to traditional BMPs
- Planning departments lack training to review and inspect LID controls
- Developers lack knowledge of LID
- LID difficult to use in urban settings, difficult to retrofit
One of the more interesting solutions to the obstacles focused on funding of “high traffic” demonstration projects to help provide a local proof of benefit.
The report can be read in its entirety here.
Watershed Imperviousness: 3 Recent Studies
Numerous studies have been conducted over the years that correlate the degree of imperviousness of a watershed to overall quality of surface waters fed by that same watershed. Three studies completed in the last few years are worth noting:
- Long Island Sound Region Impervious Surfaces Mapping Project - looks at 17 years worth of satellite imagery to predict imperviousness.
- Paving Paradise: Watershed Imperviousness and Peak Streamflow - critically examines 7 different techniques of predicting imperviousness.
- Measuring the Impact of Development on Maine Surface Waters - of particular interest is the methodology for predicting imperviousness using polygons.
Neighborhood Sidewalk/Street Watering Survey
This is a little impromptu survey that I ran over the last two nights in my neighborhood. While walking the dog at 11pm, I found roughly 10% of my neighbors were overwatering their lawns or missing their lawns altogether – and watering the sidewalks and streets.
If I estimate that each house had 6 half circle nozzles (1 GPM) and 4 quarter circle nozzles (0.5 GPM), that gives me a total rate of 8 GPM. The total average cycle appeared to be 10 minutes – resulting in 80 gallons per household. In most cases sprinklers were completely overspraying, but I will estimate that only half of this volume was runoff. If I make the assumption that each of these households operated sprinklers on a 3 day a week program, then that would give me 120 gallons of runoff per household per week. This results in a total annual runoff volume of 6240 gallons. Take the 23 homes that I surveyed (represented by the yellow blobs on the aerial photo) and you get a total anual runoff volume of 143,520 gallons for my neighborhood during the 11 o’clock hour.
And that’s just one hour in the day.
