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Low Impact Development in Connecticut

green roof at UConnConnecticut towns are increasingly recognizing the impact of stormwater runoff on water quality. Low impact development (LID), also called green stormwater infrastructure, is a major strategy to address these issues. The Nonpoint Education for Municipal Officials (NEMO) program at the Center for Land Use Education and Research (CLEAR) has been working with towns on these issues since 1991. With NEMO’s 25th anniversary looming and a major revision of Connecticut’s stormwater regulations in the process of being finalized, NEMO, with the help of a UConn Extension intern, recently completed a 9-month study on the status of LID adoption in towns across the state.

LID is a broad strategy involving a number of stormwater practices designed to infiltrate runoff back into the ground, reducing flooding, erosion, and water pollution problems. These strategies include permeable pavements, green roofs, bio retention areas, and other practices designed to reduce impervious cover. Some towns have updated their regulations to allow for or even require the use of these practices where feasible. Others however have lagged behind and actually have regulations that discourage or prohibit developers, often inadvertently, from pursuing them. NEMO’s study sought to get a better handle on the progress made on this front.

The NEMO study had two phases. In Phase One, NEMO research assistant Manon LeFevre conducted exhaustive (and exhausting) internet research on the land use plans and regulations of 85 of CT’s 169 towns (the number of towns was dictated by available resources and is not a scientifically random sample). Towns were “scored” for the number of LID strategies that appeared in these documents, based on the 14 specific practices suggested in the 2009 NEMO guide Developing a Sustainable Community. A guide to Help Connecticut Communities Craft Plans and Regulations that Protect Water Quality.

In Phase Two, follow-up phone interviews were conducted for the vast majority (78) of these towns by Low Impact Development in Connecticut Manon and Kerrin Kinnear, an Extension Intern in the UConn Environmental Studies program. Kerrin and Manon doggedly pursued town planners and other municipal staff to ascertain the reasons why their town did or did not pursue LID, the greatest barriers they face related to this type of development, and if they had any recommendations for us.

As NEMO educators have long thought, the greatest driver of LID regulations at the local level are local champions—either staff or land use commissioners. Thus efforts to educate and empower those audiences are still the most effective way of making LID commonplace (table, lower left).

On the barriers side, cost and lack of educational opportunities about LID were the top vote getters (table, lower right). However, many of the barriers can also be viewed as education issues. The cost category also encompasses perceptions that LID is more expensive, although that is not always the case and education about the true costs could help that. Reluctant town staff were also among the top vote getters for barriers, but education directed at those audiences may also help allay some of their concerns. Finally, long-term maintenance was often cited as an area of concern and more could be done through education and assistance to help address that.

In sum, the results of the NEMO LID study provide some useful information to help guide the future municipal assistance efforts of CLEAR, CT DEEP, and others. Most towns in Connecticut seem to have at least some language related to low impact development (LID) in their plans and regulations, largely due to the work of dedicated local proponents. However, not all of this this leads to regulations outlining specific LID practices, and additional resources are needed, with incentive funding and education leading the list of needs. This project was partially funded by UConn Extension and CT DEEP.

CLEAR Keeping Track of Stormwater on UConn Campus


Oak Hall bioretention. Photo: Mike Dietz

Although UConn is in the midst of a pastoral setting in the quiet corner of northeast Connecticut, we sometimes have problems like a big city. This is because the buildings, roads, parking lots and sidewalks that make up the core of campus do not allow water to pass through into the ground. Instead, rainfall is directed into storm drains, and ends up heading towards either the Fenton River to the east, or Eagleville Brook to the west. All of the excess stormwater and pollutants that get picked up along the way cause problems with the aquatic life in these rivers. The CT Department of Energy and Environmental Protection has identified Eagleville Brook as impaired. UConn Extension’s Center for Land Use Education and Research (CLEAR) has been involved in efforts to reduce the impacts of all of these impervious surfaces on Eagleville Brook. Green infrastructure practices like bioretention, green roofs, and pervious pavements have been installed around campus to help restore a more “natural” hydrologic balance. A Total Maximum Daily Load (TMDL) has been established for the brook, with impervious cover as the “pollutant” (read more about this project at An interactive map tour with photos and videos is available online here.

With all of the changes taking place on campus, keeping track of the actual impacts of the green infrastructure implementation is not an easy task. Traditional water monitoring could be done, but this is very expensive and time consuming. Recently, UConn Extension Educator Michael Dietz at CLEAR created a unique system to estimate the benefits of the green infrastructure on campus. This tracking system uses real precipitation data from UConn, and estimates the amount of stormwater treated by each practice installed, given how big the practice is, when it was installed, and the condition of the practice. This allows for a running total of the volume of stormwater treated. Through June 2014, more than 42 MILLION gallons of stormwater have been treated! To put this in perspective, this is enough to fill more than 63 Olympic sized swimming pools!

This information is being used to track progress on the TMDL, along with other regulatory obligations between UConn and DEEP. Dietz plans to continue this tracking, along with other monitoring he and Jack Clausen perform on Eagleville Brook (real-time data available here).

LID versus Green Infrastructure

If you deal with stormwater issues or land use planning, chances are you have heard the phrase “green infrastructure” mentioned a lot recently. It is rapidly replacing “Low Impact Development” (LID) as the phrase du jour in the stormwater biz. But before we all go willingly adopting this into our lexicon, we must first ask some pertinent questions.

1. What does green infrastructure mean?

If you Google (or Bing, if that’s how you roll) the phrase “green infrastructure” you will discover two related, but slightly different, definitions. Originally the term was used in land conservation circles to describe a planned and managed network of natural resources (forests, open space, waterways, etc.) in a community or watershed. The idea was that we can maximize the environmental benefits these areas provide to our communities by strategically planning where they are and how they can connect. This is very similar to what we have often referred to here at CLEAR as Open Space Planning.


More recently, the term has been adopted by the water quality world to refer to approaches that divert stormwater (i.e., rain/snowmelt) into natural areas, rather than directly into storm sewers (a.k.a. “grey infrastructure”). In doing so, you reduce the quantity impacts of stormwater (flooding, CSOs, etc.), as well as the quality impacts by removing pollutants through natural processes/filtering. Green infrastructure in this context includes utilizing rain gardens/bioretention, rain barrels/cisterns, green roofs, permeable pavements, bioswales, land conservation, urban trees and more.

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