Background - Bacteria
Bacteria carried in stormwater runoff is cause for concern as it can pose health risks and have an economical impact. The introduction of disease-causing bacteria and viruses can come from a variety of sources such as failing septic systems and boat discharges, livestock, waterfowl, and even the family dog. The harm from bacterial contamination includes the closure of shellfish beds and swimming areas and making water from both groundwater and surface water unsafe to drink.
A frequently mentioned source of bacterial contamination is from human waste. A septic system failure may result in bacterial contamination of groundwater or surface water. There are many reasons a septic system could fail: improper maintenance, overload of wastewater, poorly sited or constructed systems, tree roots obstructing the leach field or pipes, or old age - 20 years is the average life expectancy of a system. Septic system failure may result in an overflow onto your lawn or a back up of sewage into your house. Wastewater may also leak into the ground, contaminating ground water, or over flow across the ground and into a nearby stream, lake or estuary.
Bacteria from human waste may also be entering our water from boat discharges. It is illegal to discharge raw sewage or gray water from a boat into any inland water body or within 3 miles of the sea coast. Boat owners should always use pump-out facilities at marinas and ask questions if they are unsure of how to use the pump. Also, just like septic systems, regular and proper maintenance will help prevent problems. If the boat doesn't have a 'head', plan ahead by using facilities on shore or plan to pack out any waste.
Livestock is another source of bacteria pollution. In the past, it was more common for farmers to allow their livestock access to streams and ponds that flowed through their pastures; unfortunately some still do. Livestock access to Maine's waters results in shore and bank destabilization from the heavy animal traffic. While in or adjacent to the stream, horses, cattle or other livestock may leave piles of manure, which contain both nutrients and bacteria which are easily washed into the stream during the next rain storm.
More recently, local Soil and Water Conservation Districts and the USDA's Natural Resource Conservation Service have been working with farmers to develop manure management plans and grazing systems. These plans may include manure storage practices, alternative watering systems, fencing livestock out of shoreline areas to keep them away from the water, and even replanting vegetative buffers. Vegetated buffers consist of trees, shrubs and grasses planted along the shoreline. They are used to keep animals away from the water, to absorb the impact of rain before it hits the ground and loosens/washes away soil, and to filter nutrients from stormwater before it enters a waterbody.
Livestock manure is not the only type of animal waste that can cause problems. Bacteria found in pet waste also threatens our water bodies. In fact, in some urban areas of this country, pet waste is the leading source of bacteria contamination. A simple solution to this problem is to pick up after your pet when you take them for walk and periodically pick up your yard. Pet waste should be disposed of in the garbage or a pet waste composter. Be sure to always carry a plastic bag when walking your dog.
Waste from geese and other water fowl is also a source of bacteria. During the summer months, you often see a flock of geese along a grassy shoreline. While geese and other waterfowl naturally occur on lakes, we sometimes increase their numbers by feeding them directly (example, feeding bread) or indirectly (by creating grazing areas by having our our lawns go down to the edge of the water). Both activities can result in large numbers of waterfowl. When present in large numbers, they increase the amount of nutrients and bacteria in the lake. To keep the numbers of waterfowl at a more natural level don't feed them and plant a vegetated buffer.
Go to: Nutrients, Soil, Thermal, Toxics
