Appendix C City of Bowie Environmental Infrastructure Action Strategy Plan Staff Findings and Recommendations By Sub-watershed Appendix C I. Background There are twelve (12) sub-watersheds in the City limits. Four (4) of them (the Upper, Middle, and Lower Collington Branch and the Black Branch) are in the Western Branch watershed and eight (8) of them (Horsepen Branch, Saddlebrook Branch, Overbrook Branch, Millstream Branch, White Marsh Branch, MSTC Branch, Green Branch and Mill Branch) are in the Upper Patuxent watershed. In 2003, Watershed Restoration Action Strategy (WRAS) Plans were completed for both the Western Branch and the Middle Patuxent Watersheds. These WRAS plans were a follow-up to the 1998 Clean Water Action Plan (CWAP), in which both the Western Branch and Middle Patuxent watersheds were designated as being in need of restoration and protection. Each WRAS consists of four (4) components: a nutrient and biological synoptic survey, a visual stream corridor assessment (SCA) survey, a watershed characterization, and a final action strategy report. The WRAS inventory was compiled using SCA Survey Protocol developed by the Maryland Department of Natural Resources (MDNR).1 Utilizing the general descriptions of WRAS challenges found below, city staff created the attached forms for each of the twelve (12) sub-watersheds in Bowie. Each form has two maps showing the location of the sub-watershed in the City and the location of all of the challenges in the sub-watershed by site identification number. Consultants from Environmental Resource Management (ERM), prioritized the top challenges by sub-watershed based on the identified major pollutant in each sub- watershed (see Appendix A, Table 1A). II. Challenges The following eight (8) Environmental Challenges were documented in the WRAS: • Inadequate Buffers • Pipe Outfalls • Erosion • Channel Alteration • Exposed Pipes • Trash Dumping • Fish Barriers • Unusual Condition or Comment 1 http://www.dnr.state.md.us/watersheds/surf/proj/wras.html ii Appendix C Below is a definition of each of the challenges with some recommended actions that can be taken to correct the problem. Most of the information can be found in the WRAS Stream Corridor Assessment Survey Protocols.2 Inadequate Buffers: Forest buffers help shade the stream preventing excessive solar heating, which reduces its oxygen holding capacity and raises water temperatures above the tolerance limits of some fish species. The buffers remove nutrients, sediment, and other pollutants from stormwater runoff, which reduces nutrient loadings to the Chesapeake Bay. The leaves of the trees are a major component of the stream’s food web and the tree roots stabilize the stream bank, preventing erosion. MDNR purposely looked for areas with inadequate buffers during the stream survey to determine where additional forest buffers could be created to reach their goal of creating 1,200 miles of stream buffers by the year 2010. While there is no single minimum standard, buffers are considered inadequate if they are less than 50 feet wide from the edge of the stream. Corrrectability: Open areas without trees exist because they are maintained that way. If left alone, the trees will grow and a forest will eventually develop. Recommendations: Develop a ‘no mow’ policy for public lands adjacent to streams. Develop a program to educate the public of the benefits of not mowing near streams and allowing the forest buffer to increase in size. Fence the area and erect signage to alert the public and maintenance staff to the purpose of letting a forest develop. Pipe Outfalls: Pipe outfalls are any pipes or manmade channels that discharge directly into the stream. They are considered a potential environmental problem when they carry uncontrolled runoff. This runoff originates from yards, parking lots, and streets and often contains pollutants such as oil, heavy metals, and nutrients. It can have a dry-weather discharge that has a color or smell indicative of specific pollutants whose source may be traceable. Uncontrolled runoff is referred to as non-point source pollution when the water does not derive from a single, identifiable location such as a factory or wastewater treatment plant. Corrrectability: Dry-weather discharges from storm drain systems, sewage or industrial sites are expensive to correct because they usually involve major engineering requiring significant funding. Recommendations: Add rock below the outfall to soften the flow of the water and reduce sediment pollution in the stream. Reduce the amount of stormwater entering the stream by creating rain gardens and bio-retention areas on sites with large quantities of stormwater runoff. This will prevent some stormwater from entering the stream by retaining it on site. Also, pipe outfalls can be rerouted to drain through the forest buffer before entering the stream. This will slow down the flow of water and allow for some of the water to enter the ground and be filtered of pollutants before reaching the stream. A more expensive solution is to 2 http://www.dnr.state.md.us/streams/pubs/SurveyProtocols2.pdf iii Appendix C build stormwater management ponds adjacent to the streams to collect and store the water from pipe outfalls during rain events allowing the water to more slowly enter the streambed over a longer period of time. Erosion: While erosion is a natural process and a certain amount of erosion is to be expected, too much erosion can destabilize the stream bank, destroying in-stream habitat and causing additional sediment to flow downstream. As an area becomes more urbanized and the amount of impervious surface area increases, the amount of stormwater runoff increases and the additional quantity of water can erode the streambed and banks while the stream expands in size to accommodate the additional water. This results in additional sediment pollution downstream. One of the main goals of the Chesapeake Bay program is to reduce sediment inputs to the Bay. Corrrectability: Can be difficult and expensive to correct. Recommendations: Plant additional vegetation on the stream bank to slow the flow of the water and reduce sediment pollution in the stream. Reduce the amount of stormwater entering the stream by creating rain gardens on sites with large quantities of stormwater runoff. This will prevent some stormwater from entering the stream by retaining it on site. Also, pipe outfalls can be rerouted to drain through the forest buffer before entering the stream. This will slow down the flow of water and allow for some of the water to enter the ground before reaching the stream. A more expensive solution is to build stormwater management ponds adjacent to the streams to collect and store the water from pipe outfalls during rain events allowing the water to more slowly enter the streambed over a longer period of time. Channel Alteration: Channelization refers to the practice of straightening and/or widening a stream to improve the hydraulic capacity of the stream to quickly move larger amounts of floodwaters through an area. While channelization can be effective at reducing flooding or lowering the ground water table in an area, it can also have a variety of negative environmental impacts. Channelized streams can be barriers to fish migrations and often have poor habitat for aquatic organisms, particularly if the channel has been straightened by constructing a smooth, concrete channel. Corrrectability: Usually difficult and expensive to correct. Recommendations: Could be quickly altered using a backhoe if there is room for this type of restoration work. Otherwise sinuosity can be recreated in the stream by adding sediment depositions to the stream bottom at random intervals. Exposed Pipes: In urban areas, it is common for pipelines to be located in stream corridors where the land elevation is at its lowest point. Gravity sewer lines, in particular, depend on the continuous downward slope of the pipeline to carry sewage to a pumping station or iv Appendix C wastewater treatment plant. Exposed pipes are pipes that were once buried and are now vulnerable to damage during a flood or high water event because they can be seen along the stream bank. Debris from a storm can puncture an exposed pipe, which will result in fluids leaking from the pipe. This can cause serious water quality problems if the fluids are unsanitary or toxic. Exposed pipes can also cause fish blockages depending on their location in the stream. Corrrectability: Usually very expensive to correct because it often requires the use of heavy equipment. Recommendations: Cover the pipe with stone or reinforce the area around the pipe with concrete to prevent the pipe from being punctured. Also, attempt to divert the stream away from the pipe to prevent further erosion and exposure. The stream bank near the pipe should be stabilized to prevent further erosion. Trash Dumping: Can be sites where trash has been dumped from a vehicle or where trash accumulates in the stream due to a blockage. Trash can interfere with the establishment of emergent aquatic plants and can be hazardous to wildlife through entanglement in or ingestion of floating debris. When certain types of debris leach toxics, such as oil from used oil quart containers, trash can have negative chemical and biological impacts. Corrrectability: Trash dumping usually occurs where there is good vehicle access to a stream and can be successfully corrected by restricting access. Recommendations: While removing trash from upstream locations has a more minor effect on overall water quality downstream, stream clean-ups are good community activities that foster awareness. Trash removal in a given stream is an opportunity for the community to learn more about current water quality and the effect stormwater runoff has on local stream conditions. Fish Barriers: Fish migration barriers are anything in a stream that prevents fish from moving upstream. With a fish blockage present, there is no way for fish to repopulate a segment of the stream that has become isolated from its downstream counterpart.