Thursday, December 20, 2007

Shoreland Buffers

As reported in this paper and elsewhere, the City of Minnetonka recently pulled back on their proposed shorland buffer proposal. I, representing the Lake Minnetonka Association, attended the November 27th City Council listening session and spoke against that provision of the proposed shoreland ordinance. Here is why.

The proposed vegetated buffer in the shoreland zone was intended to improve water quality because vegetated buffers can reduce pollution in runoff compared to “unbuffered” areas. While this is technically true, closer examination reveals this concept was not well-conceived.

Simply, as proposed, the ordinance was a solution in search of a problem.

First of all, vegetated buffers remove certain kinds of pollution differently. For example, suspended sediments can be removed very effectively, but phosphorus is not removed effectively. Suspended sediments are not normally an issue in residential lakeshore properties and suspended sediments are not an issue in Lake Minnetonka, so there is no general need to mitigate these. Phosphorus can be a problem in Lake Minnetonka; however, Minnesota now restricts phosphates in lawn fertilizers, so phosphorus is not a big problem (even if the buffers could reduce it).

Second, what is the water quality problem? Gray’s Bay, the portion of Lake Minnetonka in the City of Minnetonka, has very good water quality. In fact, it has one of the highest water quality grades on the entire lake. Indeed, the overall quality and condition of Lake Minnetonka is actually very good. Water quality has been improving in many bays for the past 20 or 30 years – due in large part to diverting wastewater discharges to the lake. What water quality problems that do exist, occur in the shallow, Western bays. There, the water quality problems are due to runoff from large tributaries and not from lakeshore lawns. Also, Lake Minnetonka has one of the healthiest, most productive fisheries in the state.

Third, the proposed buffer requirement was negotiated as a trade-off to allow increased hard surface coverage in the shoreland zone. This is a bad trade-off for water quality. Hard or impervious surfaces do not allow rainfall to penetrate so it instead runs off. As more water runs off, its energy and erosive capacity increases and it tends to pick up and carry more pollution. This is especially critical in the shoreland zone.

Finally, the proposed buffers required the planting of “required” vegetation and certain maintenance prohibitions, such as no mowing or fertilizer use. However, this is a simplistic approach that is more for show than for function. We can do better.

The Lake Minnetonka Association recommends that lakeshore owners consider lakescaping as a way to protect their lakeshore. Specifically, we recommend:

“Lakescaping is simple landscaping on the lakeshore, providing a more natural alternative to structural or artificial shore landscaping and erosion control. Lakescaping can benefit Lake Minnetonka by improving fish and wildlife habitat, providing shoreline protection and enhancing the lake's aesthetics.”

There are important differences between this approach and the City of Minnetonka’s proposed vegetated buffer requirement. First, it should be voluntary. Second, notice that we do not cite water quality benefits because they are not usually a significant part of lakescaping. Third, lakescaping when done well, is an intensive, long-term project that involves planting, engineering, and restoration in the upland areas and in the lake. Typical lakescaping projects are often costly (tens of thousands of dollars) and can take two or three years to mature.

We feel, for those who value and appreciate this lakeshore experience, the costs and effort are worthwhile. But, we also feel this is an enhancement, and not a requirement.

The City of Minnetonka has a well-deserved reputation for being forward-looking and proactive with respect to environmental protection and we are grateful for that. In this case, while the City’s intentions are clearly well placed, their proposed buffer requirement was not. The Lake Minnetonka Association is grateful the City of Minnetonka has reconsidered their approach and would welcome the opportunity to work with them in the future.