SUMMARY OF WATERSHED SURVEY FINDINGS
The survey teams identified 16 sites in the Libby River Watershed that appear to be sources of polluted runoff. A few of the sites have multiple factors contributing to the problem. The surveyors recorded detailed information on the location, land use, type of polluted runoff, impacted resources, and recommendations to correct the situation. Sites were rated according to their potential impact on water quality in the receiving river, stream, pond or marsh, technical skill level needed to install the recommended solution, and the relative cost of the recommended solution. An explanation of the site evaluation ratings and a table containing the survey findings are presented in Appendix A. The site locations are shown in Figure 4.
Generally, the survey results indicate that the sites can be divided into the following four categories:
Examples of each of these categories are in Figures 5, 6, 7, and 8, respectively. Common problems associated with each category and typical solutions are also presented in the figures. More details on the problems and solutions are presented in the following paragraphs.
Landowner Practices
Landowner practices are the major source of polluted runoff in the Libby River watershed, as they are in most developed watersheds. Because watershed surveys are not able to identify the practices of every individual landowner, the survey findings do not truly represent the magnitude of the problem. However, based on the prevalence of well-manicured lawns and a suburban landscape that is characteristic of much of the watershed, it is apparent that the following landowner practices may be common sources of polluted runoff:
Lawn Fertilization. As indicated in the introduction, overuse of lawn fertilizers can result in nutrient enrichment and dissolved oxygen depletion in the receiving waters. Unlike farmers, suburban landowners typically adopt a lawn fertilization program without the benefit of knowing what their lawn needs. Soil testing is the only way of determining lawn needs. Landowners can have their soil tested by the Maine Soil Testing Service at the University of Maine. Soil containers and information forms can be obtained by contacting the Testing Service at 581-2934 or by contacting the University of Maine Cooperative Extension office in Cumberland County at 287-1471. Having your soil tested and using the recommendations of the Testing Service may
not only benefit water quality in the Libby River Watershed but may also save money that is otherwise spent on unnecessary fertilization.
Other methods of reducing or eliminating fertilizer use include:
Phosphorous-free fertilizer is available from certain retail outlets. Request that your lawn and garden center carry this product. For information, contact Eco-cycle at 622-7800.
Pesticide Application. As discussed in the introduction, some pesticides can be harmful to aquatic life even at very low levels. The use of "weed and feed" lawn care products is probably a significant component of pesticide use in the Libby River Watershed. Many people are not aware that these products contain herbicides. People that employ lawn care companies may also not be aware of the pesticides being applied to their lawns and gardens. In terms of protecting water quality, the following recommendations regarding pesticide application are provided:
Dog Walking and Not Picking Up After the Dog. As indicated in the introduction, dogs have been found to be a major source of fecal coliforms and pathogens in many urban watersheds (Center for Watershed Protection, 1999). The reasons that they have this dubious distinction are due to their high populations in residential neighborhoods and their daily defecation and bacteria/pathogen production rates, both of which are high considering the average size and weight of a dog. Dog owners will be performing their part for the protection of water quality and the appearance of their neighborhood by picking up after their dog and disposing of dog waste in a trash can, toilet, or compost pile. A potential alternative to picking up after dogs is to train them to use areas that are not next to gutters, ditches, streams, or ponds. Dog waste should not be disposed of in a storm drain inlet.
Car Washing. Outdoor car washing is another common practice that often causes landowners to unknowingly contribute to polluted runoff. The car wash detergent, combined with the grease and grime washed off of cars, can result in high loads of nutrients, metals, and oil entering ditches or storm sewer systems. To reduce or eliminate the amount of polluted runoff associated with car washing, car owners should consider the following alternatives:
Besides those described above, other landowner practices that can be altered to reduce the potential for polluted runoff include:
Vegetated Buffers
Vegetated buffers are a natural feature of an undisturbed forest. They are composed of trees, shrubs, groundcovers, and a "duff" layer that is the accumulation of decaying leaves, pine needles, and other plant material that falls to the ground. A mature vegetated buffer both slows and filters runoff before it enters a water body. Because development can strip upland areas of most of its vegetation, buffers that remain on the shoreline are the last line of defense against polluted runoff. The watershed survey found that vegetated buffers along drainageways and ponds have been replaced by lawns and beaches in some neighborhoods. In the absence of buffers, runoff carrying potential pollutants such as chemical fertilizers and pet waste from lawns have a relatively unimpeded path to drainageways and ponds. In addition, beaches that have been constructed in place of vegetated buffers on ponds are prone to erosion and eroded soil entering a pond adds potentially harmful sediment and nutrients.
Landowners interested in re-establishing vegetated buffers on their property have choices about the appearance and functions of their buffer. Those choices can be divided into three general categories (Hardesty and Kuhns, 1998):
Natural buffers are the product of not mowing a strip of land that is adjacent to a water body. Plants that are adapted to the area will establish themselves naturally with no investment in time, money, or energy required on the part of the landowner. The drawbacks of a natural buffer for some people are that it may take a number of years for mature vegetation to become established and the landowner has limited control over the type of plants growing in the buffer.
Enhanced buffers are appropriate for landowners who want to supplement existing buffer vegetation or who want to influence the composition of their buffer. Although there may be a moderate investment in the purchase and placement of plants, the landowner will have a buffer that better suits their personal preferences and that matures within a shorter period of time.
Landscaped buffers require considerably more planning in the layout and selection of plants than do the other buffer categories. The landowner should visualize how they want the buffer to appear as it matures and should consider the maintenance needs required to control competition between the plants and to prevent the invasion of unwanted indigenous plants. Although the cost and effort may be relatively high, the landowner has complete control over the buffer design.
Depending on the buffer category that a landowner selects, there are several factors that should be considered in buffer design:
Stormwater Management Systems
New residential and commercial development is subject to Maine Stormwater Rules, which regulate the quantity and quality of stormwater leaving a project. Although all stormwater is not polluted, the use of the term "stormwater" is synonymous with "polluted runoff’ for purposes of this report. Because the Stormwater Rules went into effect in 1997, much of the development in the Libby River Watershed that pre-dated the Stormwater Rules was not constructed in accordance with the strict standards that are in effect today. Typically, stormwater from new developments is not discharged into a water body until it passes through a control structure, such as a detention pond, that prevents downstream flooding and provides treatment. Stormwater from older developments normally discharges directly into a water body. If properly designed, constructed, and maintained, the stormwater that discharges from control structures is relatively free of sediment and other pollutants as compared to stormwater that is discharged directly into a water body. The Stormwater Rules are designed to protect water bodies from stormwater associated with individual projects, however, there currently is no stormwater master plan for protecting the Libby River and its tributaries from the cumulative effects of stormwater runoff from existing and future development in the watershed.
The watershed survey documented visual observations at stormwater outfalls (i.e., discharge pipes from storm sewer systems) such as discolored sediment or an oily sheen on the water. These types of observations were noted at a few outfalls and are an indication that polluted runoff has entered the storm sewer systems from the neighborhoods that they serve. These observations reinforce the importance of landowners adopting practices that are protective of water quality. This is true of new developments with control structures, as well as older developments, because control structures do not have 100 percent pollutant removal efficiency.
Stormwater control structures that were encountered during the watershed survey were inspected for deficiencies that might compromise their effectiveness. Most of the control structures had some type of problem that resulted from the lack of maintenance or repair. These problems likely result in a reduced effectiveness at controlling the amount of stormwater and stormwater pollutants that are discharged into the headwater streams of the Libby River. Unfortunately, maintenance of stormwater control structures is overlooked in many municipalities partly because it is often unclear as to what individual or organization is responsible for their upkeep and there is little follow-up by the regulating authority. Transfer of maintenance responsibilities from a developer to a municipality or a landowner association must be approved by the Maine DEP and that organization must comply with all terms and conditions of the permit to discharge stormwater.
Soil Erosion
Soil erosion does not appear to be as serious a problem in the Libby River Watershed as it is in some other developed watersheds. Soil erosion is often a product of poorly designed and/or maintained gravel roads, driveways, ditches, trampled ground on footpaths and woods roads, and construction sites. These types of land uses were not widely observed during the watershed survey but the watershed is still under periodic development and soil erosion from construction sites will remain a concern. By law, it is the responsibility of the construction contractor to install and maintain erosion and sediment controls at a construction site.
The most practical and cost-effective method to prevent sediment from entering water bodies is to prevent soil erosion from occurring in the first place. This can be accomplished by vegetating, mulching, or covering bare soil with erosion control blankets. The erosion control market has evolved to the point where there is now a product for almost any type of soil erosion challenge.