CORSICA RIVER PRELIMINARY WATERSHED AUDIT. Opportunities To Build Upon A Highly Successful Watershed Restoration Campaign CORSICA RIVER CONSERVANCY

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1 CORSICA RIVER PRELIMINARY WATERSHED AUDIT Opportunities To Build Upon A Highly Successful Watershed Restoration Campaign Prepared By Richard Klein COMMUNITY & ENVIRONMENTAL DEFENSE SERVICES 811 Crystal Palace Court Owings Mills, Maryland Help@ceds.org ceds.org/audit On Behalf of CORSICA RIVER CONSERVANCY Post Office Box 235 Centreville, Maryland June 10, 2012

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3 CONTENTS SUMMARY...1 A PHENOMENAL RESTORATION EFFORT...1 CURRENT CONDITIONS & IMPAIRMENT SOURCES...1 AUDIT FINDINGS & OPPORTUNITIES TO ACCELERATE RESTORATION...3 Construction Sites...3 Stormwater BMPs...3 Conservancy Rain Gardens...4 Retrofits...4 Forest Conservation...5 Environmental Site Design...5 Centreville WWTP: An Impressive Success...5 Sewage Collection System...6 Illicit Discharges...6 Cover Crops...6 Buffers...6 Concentrated Animal Feeding Operations (CAFO)...7 Sewage Sludge Application...7 INTRODUCTION...8 CORSICA RIVER CURRENT CONDITIONS & IMPAIRMENT SOURCES...8 NUTRIENT TOTAL MAXIMUM DAILY LOAD (TMDL)...11 WATERSHED RESTORATION ACTION STRATEGY (WRAS)...12 MARYLAND BIOLOGICAL STREAM SURVEY (MBSS) DATA...13 ECOLOGICAL ASSESSMENT...15 IMPERVIOUS SURFACES & ESTUARINE HEALTH...17 SUMMARY OF CURRENT CONDITIONS & AUDIT RELEVANCE...18 AUDIT OF REGULATED & OTHER AQUATIC ENHANCEMENT ACTIVITIES...19 WHY SITE NAMES & LOCATIONS ARE NOT GIVEN IN THIS REPORT...19 CONSTRUCTION SITE EROSION & SEDIMENT CONTROL...20 Why Does Exposed Soil = Pollution?...21 Construction Site Audit...22 EXISTING STORMWATER BEST MANAGEMENT PRACTICES...24 Development Project BMPs...24 Conservancy s Amazing Retrofit Project...27 Other Retrofits...28 FOREST CONSERVATION...29 ENVIRONMENTAL SITE DESIGN...31 POINT SOURCE DISCHARGES...33 ILLICIT DISCHARGES...36 COVER CROPS...39 BUFFERS...41

4 CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO)...43 SEWAGE SLUDGE APPLICATION...43 Tables 1. Corsica River Watershed Characteristics TMDL Nutrient Sources (Yr 2000) Fish Health Comparison Nutrient Sources Assessment Stormwater Best Management Practices Serving Corsica River Watershed Development Stormwater BMP Audit Findings Corsica River Reported Sewage Overflows Present Corsica River Stream Sampling Results - 14 March Cropfield Nitrogen Loading & BMPs...39 Figures 1. Corsica River Watershed Map Centreville Spray-Irrigation Monitoring Well Data...35

5 SUMMARY Thanks to a grant from the Chesapeake and Atlantic Coastal Bays Trust Fund the Corsica River Conservancy retained Community & Environmental Defense Services (CEDS) to conduct a Preliminary Watershed Audit for the Corsica River. A PHENOMENAL RESTORATION EFFORT Beginning in the late 1970s, the author of this report was the director of Maryland Save Our Streams. I launched one of the first watershed restoration campaigns in Maryland, which targeted Gwynns Falls in Baltimore County and City. Over the past four decades I ve watched many similar projects strive for success. But it was not until I had the pleasure of studying the Corsica River effort that I ve seen a restoration project so unequivocally successful. The Corsica River Conservancy attracts one in four watershed residents to their annual Awareness Day. One in five households benefits from a Rain Garden and a number of others have rain Barrels. The Town of Centreville has produced one of the best wastewater treatment facilities on the Eastern Shore. The Town in conjunction with the County, State agencies and private foundations has implemented dozens of restoration practices. The farming community of the watershed, with support from the Queen Anne s Soil Conservation District and the Maryland Department of Agriculture, has achieved the most extensive use of winter cover crops in Maryland and perhaps in the entire Bay watershed. Thanks to all of these incredible efforts the Corsica River is well on the way to becoming the first fully restored waterway in the Chesapeake Bay drainage. But the River is not there yet and a number of challenges remain. The purpose of a Watershed Audit is to provide a thorough, independent assessment of all activities regulated by existing aquatic resource protection laws. A Preliminary Audit, such as that described in this report, takes a first look at a sampling of regulated activities. However, the Corsica River watershed is unique in having benefitted from so many restoration activities. Because of this a number of voluntary aquatic resource enhancement activities have been included in this Preliminary Audit. In the following pages several opportunities to improve the aquatic resource benefits of these activities are offered. The shortcomings are not due to any lack of motivation or dedication on the part of the many people who oversee these activities. Instead, the problem lies in the fact that they are too few in number and lack the resources needed to succeed. CURRENT CONDITIONS & IMPAIRMENT SOURCES The tidal portion of the Corsica River is suffering from excessive nutrient and sediment inputs which lowers water clarity and inhibits the growth of submerged aquatic vegetation along with beneficial benthic algae, both of which are essential to a healthy ecosystem. The nutrients stimulate excessive surface algal growth which reduces water clarity and leads to severe oxygen depletion. Suspended sediment combines with algae to further reduce water clarity. 1

6 To restore the tidal portion of the Corsica River, a 2009 University of Maryland Center for Environmental Science assessment called for reducing nutrient inputs by 50%, which would bring about a 70% reduction in algae and a substantial improvement in water clarity. University scientists recommended achieving this 50% reduction by: maximizing the use of winter cover crops on half of all agricultural fields; increasing the removal of nutrients from runoff generated on developed lands with stormwater Best Management Practices (BMPs); and upgrading the existing 160 (of 809) septic systems located near tidal waters for better nitrogen removal. Four percent of the Corsica River watershed is presently covered by buildings, parking lots, streets and other impervious surfaces that prevent rainwater from infiltrating underlying soils. A recent study found that tidal rivers, like the Corsica, begin suffering even more acute water quality problems when watershed imperviousness exceeds 5%; a threshold the River may soon cross. However, the adverse effects of increasing growth can be offset by retaining more forest and utilizing highly effective stormwater BMPs. The nontidal portion of the Corsica River system consists of three major streams: Gravel Run, Mill Stream Branch, and Three Bridges Branch. Based on fish and macroinvertebrate sampling, these nontidal waters are presently rated fair on a scale of poor, fair and good. Of the three, Gravel Run is slightly better than Three Bridges Branch with Mill Stream Branch slightly poorer. The factors cited as degrading the quality of nontidal portions of the Corsica River system include: Lack of riparian buffers; Excessive sediment inputs which degrade habitat by filling pools and riffles, burying woody substrate, lowering stability and reducing variations in stream velocity-depth; Low percentage of the watershed in forest; and Some nontidal stream segments are presently affected by development which will increase as growth continues in the watershed, though full use of erosion and sediment control, Environmental Site Design and other highly-effective aquatic resource protection measures could substantially reduce the impact. While nutrients tend not to be a significant problem for smaller nontidal streams, these waters do convey nutrients to the tidal river. Researchers have isolated five nitrogen hotspots along these nontidal waterways and hope to identify and correct the cause of each. 2

7 AUDIT FINDINGS & OPPORTUNITIES TO ACCELERATE RESTORATION Following is a summary of the findings from each Audit area. In the main report recommendations are offered with regard to steps the Conservancy can take to further accelerate Corsica River restoration. Construction Sites Sediment (eroded soil) is a major factor in the decline of the tidal Corsica River and tributary streams. No land use has the potential to generate more sediment on a per acre basis than construction sites. Erosion control is the most effective method for preventing construction site sediment pollution. Once a site is cleared and brought up to rough grade all disturbed soils must be treated with a layer of straw mulch sufficiently thick to obscure underlying soils and seeded with grass. Additional seeding may be required to achieve adequate stabilization. Thorough stabilization reduces erosion and sediment pollution by 95% to 99%. Perimeter controls, like black silt fence and sediment traps, reduce pollution by a third to half but allows the most harmful soil particles (clay) to escape. CEDS identified five construction sites within the Corsica watershed. One had a very large soil stockpile that had not been properly stabilized and was severely eroded. Though a sediment trap had been installed to intercept runoff from the stockpile the trap had filled with eroded soil quite some time ago. Since then large quantities of sediment have been discharged into Mill Stream Branch. This very serious problem was referred to the Maryland Department of the Environment. MDE quickly investigated and directed the owner make all necessary corrections. The four other construction sites were residential projects where a portion of the graded, but undeveloped lots had not been stabilized as required by State law. The lack of stabilization ranged from complete to perhaps 50% vegetative cover; well short of the coverage needed to protect nearby waters. While some of these lots drained to large sediment basins, the lack of full stabilization allows excessive sediment releases into the Corsica River system. MDE s inspection capabilities are limited to put it mildly. Though State law requires biweekly inspections of all construction sites, only 16% of those under MDE jurisdiction are visited in any given year. Several options are available for improving erosion control compliance in the Corsica River. The first and most effective would be to establish a cooperative relationship with developers and contractors where Conservancy volunteers keep an eye out for opportunities to enhance stabilization. Another option would be for the Town of Centreville or Queen Anne s County to assume inspection-enforcement responsibility from MDE. Stormwater BMPs About 7% of the Corsica River watershed is developed with homes, businesses, schools, etc. And about 10% of the nitrogen and 25% of the phosphorus entering the tidal Corsica River is washed from these buildings, associated parking lots, streets, sidewalks and other impervious surfaces. Fortunately, two-thirds of all impervious surfaces drain to 85 stormwater Best 3

8 Management Practices. These BMPs include ponds, specially designed grass channels, bioretention facilities and infiltration trenches or basins. If all of the BMPs were working perfectly they would keep the following quantities of pollutants out of the Corsica each year: 2,543 pounds of nitrogen, 480 pounds of phosphorus and 127 tons of solids (mostly soil eroded from channels). However, a survey of 48 of the BMPs indicated that about half had maintenance issues or other defects that would lower pollutant removal efficiency. In a few cases the defects were such that pollutant retention had dropped to zero and a facility was even in danger of washing out. Stormwater BMP inspection and maintenance is a major problem statewide. Presently those who own BMPs in Queen Anne s County are responsible for maintenance whether the owner be a government agency, a homeowners association, a business or church. The Maryland General Assembly recently passed two bills to address stormwater inspection-maintenance funding, but the bills (HB987/SB614) did not include Queen Anne s County. However, the Town of Centreville is considering the possibility of creating a stormwater utility which would generate the funds needed to effectively inspect and maintain BMPs, within this portion of the watershed. Conservancy Rain Gardens Through an innovative and highly effective program, the Corsica River Conservancy has succeeded in accomplishing something no other watershed group has achieved in Maryland, perhaps even nationally. The Conservancy has won the support of one out of every five watershed homeowners for their Rain Garden program. There are now nearly 37 Rain Gardens in the watershed with more coming. The key to this highly successful effort are Conservancy volunteers who give homeowners a choice of Rain Garden design, the homeowner selects the spot to install the Rain Garden, then a contractor comes by to install each facility by hand. The Rain Garden costs $2,000 each for a total expenditure of $740,000 thus far. These funds were provided by the Chesapeake and Atlantic Coastal Bays Trust Fund and the National Fish and Wildlife Foundation (NFWF) administered through the Chesapeake Bay Trust. Equally impressive is the degree to which homeowners have maintained the Rain Gardens. Only 3% have failed! The only shortcoming is that a number of the Rain Gardens lack a depression at the surface to store impervious surface runoff until it can soak through the mulch and planting soil layers. Retrofits In addition to the Conservancy s 370 Rain Gardens, the Town of Centreville, Queen Anne s County, the Maryland Department of Natural Resources and the Maryland Department of the Environment have or soon will complete 32 other retrofit projects. Most of these projects were identified in the 2004 Corsica River Watershed Restoration Action Strategy or grew out of subsequent planning efforts. 4

9 Forest Conservation Since the mid-1980s development projects within the critical area, which extends 1,000 feet from high tide, have been required to preserve a portion of each site as forest. All other development has been required to meet similar forest conservation requirements since These forest areas are then recorded on the plat for each project as Forest Conservation Easements. The plats were obtained for three major Corsica River watershed development projects approved since forest conservation requirements came into effect. One has built out completely and the other two project sites have been cleared and partially completed. On one project there is a 6.5-acre riparian buffer area adjoining an intermittent and perennial stream which was supposed to be converted to forest but has remained in agricultural production. The Conservancy is pursuing this matter to verify that this area was supposed to be forested. At another project it appears that a 30-acre forest conservation easement may extend onto adjoining properties, which could increase the likelihood that the forest would be disturbed. The Town of Centreville is looking into this question. Environmental Site Design In 2007, Queen Anne s County adopted the first Environmental Site Design manual of any Maryland county. In 2009, ESD was adopted statewide. ESD is a far more effective way of getting the benefits of growth with fewer aquatic resource impacts. CEDS reviewed the plans for all development projects proposed for the Corsica watershed, but which have not yet been built. There were three such projects. All were approved prior to the adoption of ESD. Nevertheless several are using elements of ESD. Recommendations are offered in the body of this report for how the Conservancy might encourage all three owners to make greater use of ESD. Centreville WWTP: An Impressive Success The Centreville wastewater treatment plant (WWTP) treats less than 350,000 gallons per day (gpd) from a population of about 4,285 people. Prior to the 2004 Corsica River Watershed Restoration Action Strategy, the plant discharged 11,500 pounds of nitrogen annually into Gravel Run near where it enters the tidal Corsica River. The Town has since installed a highly-effective wastewater treatment system and switched the discharge to spray-irrigation fields located along MD 305, east of downtown. Nitrogen releases has been slashed by an amazing 59%! Groundwater monitoring records show that the high quality effluent sprayed on the MD 305 site actually reduces nitrogen concentrations in groundwater. In other words, the effluent is cleaner (in some respects) than groundwater flowing onto the site. Beginning in 2007, the nitrogen content of groundwater flowing beneath MD 305 and onto the spray site began declining. While it is tempting to believe this is due to BMPs applied to cropland this is but one of a number of possible explanations. One set of data does raise concern about the effect of the spray-fields and warrants further investigation. Generally macroinvertebrate sampling showed good conditions throughout Three Bridges Branch except at two stations rated fair which are located next to the spray-irrigation fields. However, both stations are also improving which indicates some past impact that has 5

10 been resolved. The impact could have occurred during the development of Three Creeks which sits on the opposite bank of Three Bridges Branch. These and other possible causes warrant further investigation. Sewage Collection System The less than 350,000 gallons of sewage treated at the Centreville plant each day is collected from 1,000 homes, businesses and other buildings via a system of buried pipes (sewers) and five pumping stations. According to the Maryland Department of the Environment, slightly more than one million gallons of sewage has been released from the sewage collection system and into the Corsica River system since Most of the release was due to severe weather events. But the number of incidents has declined sharply since Only one such incident occurred last year. Illicit Discharges Occasionally a manufacturing or repair operation will connect a wastewater discharge pipe to a storm drain. This is illegal and is termed an illicit discharge. To check for such discharges one examines each pipe outfall (of which there are at least 57 in the Corsica watershed) to look for anything flowing from the pipe in dry weather. If flow is present and it is something other than clear, cool, odorless groundwater then samples are collected to test for pollutants. This is what was done by those who prepared the Watershed Restoration Action Strategy. For this Preliminary Audit waters associated with each stormwater BMP were examined for pollution indicators. Most BMPs are located below storm drain outfalls. Also, 21 points on streams in the Corsica system were analyzed for pollution indicators. Only one suspect area was found which is likely due to large amounts of road salt applied at the MD213/US301 interchange. Cover Crops Agriculture dominates the Corsica River watershed with regard to land use and nutrient releases. The 45 farmers who work these lands have taken many important steps towards minimizing nutrient and sediment releases. The most recent of which is a very impressive increase in the use of winter cover crops. A well-timed and established cover crop can reduce nitrogen and sediment loads by 47% and 20%, respectively. All of the fields in the watershed which could benefit from cover crops did so in These were mostly the fields planted in corn last year. In March, CEDS viewed these fields from adjoining roads and found a well-established cover crop on most. However, survey in April, May and June indicated that a portion of these fields could have been planted in a commercial cover crop. Some commercial winter cover crops receive fertilizer which reduces the nitrogen load reduction benefit. Buffers A strip of grass extending 35 feet from a stream bank can reduce the amount of nitrogen entering the waterway by 13% to 46%. A 100-foot forest buffer can keep 19% to 65% of nitrogen out of 6

11 the waterway while preserving instream habitat for fish and other organisms. The Watershed Restoration Action Strategy (WRAS) and other studies identified a paucity of buffers as a major problem of the Corsica River system. The 2004 WRAS noted 18 waterside areas rated as Very Severe or Severe with regard to the absence of a buffer. CEDS examined these 18 areas from nearby roads or aerial photos to determine how much progress has been made in the last nine years improving these buffers. Of the 18 buffers, two had some improvement but not to the degree needed to achieve full buffer benefits. A third buffer had a well established grass buffer. However, some of these areas may have been transformed to grass buffers which may not show up on an aerial photo. Since the WRAS was published in 2004, more than a hundred acres of buffers have been established in the Corsica River watershed. Concentrated Animal Feeding Operations (CAFO) Two of these operations exist in the Corsica watershed and have a combined capacity of 792,000 chickens. The Corsica River streams most closely associated with each CAFO were examined for evidence of pollution, but no such indications were found. Sewage Sludge Application Nine farms in the Corsica River watershed make beneficial use of wastewater plant sludge by applying it to fields. As with CAFOs, the waters associated with each of these farms were examined but no adverse effects were apparent. 7

12 INTRODUCTION In March, 2012, the Corsica River Conservancy retained Community & Environmental Defense Services (CEDS) to conduct a Preliminary Watershed Audit for the Corsica River. The Audit was made possible through a grant from the Chesapeake and Atlantic Coastal Bays Trust Fund. The purpose of a Watershed Audit is to provide an independent assessment of activities regulated by existing aquatic resource protection laws. The Audit identifies areas of success and need. An Audit serves as an opportunity to educate watershed residents about the benefits they derive from the successes and how their quality of life can improve if they take a more active role in supporting government and private aquatic resource protection efforts. A Preliminary Audit, such as that described in this report, takes a first look at regulated activities. The intent is to assess a sampling of each category of activity present within a watershed to determine if problem areas exist. Recommendations are then provided for resolving aquatic resource impacts caused by problem activities, including methods citizens can use to independently monitor all activities in the future. Both a Preliminary and full Watershed Audit begin with a review of available information regarding the targeted waterway. "An informed citizenry is the only true repository of the public will." Thomas Jefferson You don't get what you expect. You get what you inspect. When you deal in generalities, you will never have success; but when you deal in specifics, you will rarely have a failure. When performance is measured, performance improves. When performance is measured and reported, the rate of improvement accelerates" Thomas S. Monson, Business and Religious Leader CORSICA RIVER CURRENT CONDITIONS & IMPAIRMENT SOURCES Table 1, on the next page, provides the characteristics of the Corsica River and its watershed. A map of the Corsica River watershed (Figure 1) follows the table. The latest University of Maryland Center for Environmental Science Ecocheck assessment of the Chester River and tributaries, including Corsica River, rated these waterways a D. The 2010 Chester River Association (CRA) Report Card rates Corsica River nontidal tributaries at B- with the mainstem of the Chester River and tidal tributaries (including the Corsica) rated C-. The Ecocheck and Report Card do not use the same water quality parameters, hence the difference in ratings. Of course the ratings are based on a scale of A to F, with A being optimum water quality. 8

13 Table 1: Corsica River Watershed Characteristics Watershed area (approximate) Land Use: CHARACTERISTIC VALUE SOURCE 25,298 acres 39.5 sq mi Agriculture 60% 2 Forest 27% 2 Residential 7% 2 Water 6% 2 Wetlands <1% 2 Impervious area 4% 3 Population 5,842 6 Homes (2007 approximate) 1,500 1 Tidal River: Length 6.5 miles 1 Maximum depth 15 feet 4 Mean depth ~3.28 feet 2 Named nontidal tributary length (miles) Alder Branch Earle Creek Emory Creek Gravel Run Mill Stream Branch Miller Creek Three Bridge Branch Sources: 1. Six Years of Corsica River Restoration: January 2006 through December 2011: 2. An Ecological Assessment of the Corsica River Estuary and Watershed: CT09.pdf 3. Impervious Surface Target and Limit Reference Points for Chesapeake Bay Subestuaries Based on Summer Dissolved Oxygen and Fish Distribution, available online at: 4. ADC Chartbook Chesapeake Bay Maryland & Virginia 8 th Edition 5. Direct measurement from USGS topographic maps 6. Based on 2010 Census data which showed a population of 4,235 for the Town of Centreville and an average population density of 47.5 people per square mile outside of the Town. 1

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15 Beginning in 2000, the Maryland Biological Stream Survey (MBSS) conducted intensive sampling of Corsica River nontidal tributaries. The latest MBSS report analyzed data gathered from 2006 to Based on fish and macroinvertebrates (insects, crustaceans, worms, etc.) the nontidal tributaries are in fair condition (on a scale of poor, fair and good). Of the three major tributaries, Gravel Run is slightly better than Three Bridges Branch with Mill Stream Branch slightly poorer. The MBSS data is discussed in detail later in this report. In 1999, the Maryland Department of the Environment (MDE) placed the Corsica River on the list of impaired waters due to: excessive sediments, over-enrichment with nutrients, PCBs, fecal coliform bacteria, and impacts to biological communities. As a result of these impairments, the Corsica River was listed as a Category I watershed, in need of restoration. In 2000, MDE drafted Total Maximum Daily Load reports for three causes of Corsica River impairment: nutrients, PCBs and fecal coliform bacteria. NUTRIENT TOTAL MAXIMUM DAILY LOAD (TMDL) When present in excessive quantities, nutrients (nitrogen and phosphorus) can stimulate excessive algal growth which leads to dissolved oxygen depletion and severe stress for most aquatic organisms. Elevated algae density also blocks sunlight essential to submerged aquatic vegetation. These SAVs provide important habitat for many fish, shellfish and other Corsica River denizens. The year 2000 MDE report established an annual TMDL for nitrogen of 287,670 lbs/yr and 22,244 lbs/yr for phosphorus. Table 2, shows the sources of nitrogen and phosphorus presented in the 2000 TMDL. The sole point source was the Town of Centreville wastewater treatment plant (WWTP). Urban NPS (Non Point Source) is runoff from existing buildings, parking lots, streets and other impervious surfaces. If nutrient releases into the Corsica River system are lowered to the loadings called for in the TMDL, then dissolved oxygen levels in the Corsica River should remain at or above that required for a health ecosystem 1 and algal Table 2: TMDL Nutrient Sources (Yr 2000) Source Nitrogen Phosphorus Agricultural 86% 84% Forest 6% 2% Urban NPS 4% 3% Centreville WWTP 4% 11% growth should remain within the range compatible with a River fully suited for aquatic life, swimming and other forms of water recreation. At the time the TMDL was completed, the sewage treated at the Centreville WWTP was discharged into Gravel Run near the head of tide. Today, the effluent is applied to land at a 1 Dissolved oxygen must remain above 5.0 milligrams per liter (mg/l) to maintain a healthy, diverse community of fish and other aquatic organisms. 11

16 state-of-the-art spray irrigation facility located along the north side of MD 305, just west of Tanyard Road. During the winter months, when frozen ground precludes spray-irrigation, effluent is still discharged to Gravel Run, although the effluent is much cleaner today. According to the TMDL, in the late 1990s the Centreville WWTP was annually discharging about 11,500 pounds of nitrogen to the Corsica River. In 2010, the nitrogen release was 4,731 pounds per year - a 59% reduction! WATERSHED RESTORATION ACTION STRATEGY (WRAS) Shortly after the listing of the Corsica River as impaired waters and the release of the TMDLs, the Town of Centreville sought and received funds to prepare a Watershed Restoration Action Strategy (WRAS). The purpose of a WRAS is to guide the efforts needed to achieve the nutrient TMDL and to resolve other causes of impairment. The data required to prepare the WRAS was gathered in 2003 and the report was released in The WRAS set forth the following 13 specific action strategies: 1. Plant 4,000 acres of Cover Crops per year and 2000 acres of small grain enhancement per year to increase nutrient uptake. 2. Install 100 acres of Buffers on Agricultural Land to reduce nutrient and sediment runoff. 3. Implement 50 acres of horse pasture management. BMPs include nutrient management, grazing, and waste management system plans (ag demo project). 4. Conduct Outreach program for the Town of Centreville emphasizing Household Pollution Reduction. 5. Begin a Water Quality Monitoring program for the main stem of the Corsica River. 6. Plant Submerged Aquatic Vegetation (SAV). 7. Create Centreville Low Impact Development Ordinance and Stormwater Manual. 8. Promote Bay Friendly Landscaping: Outreach to encourage planting of native plant species; Demonstration Project to restore an environmentally impaired site; Residential Buffer Planting and Conservation Landscaping for select neighborhoods. 9. Provide Easement Incentives- Acquire development rights within the Corsica watershed. 10. Create Wetlands identify at least 2 wetland restoration sites. 11. Retrofit Septic Systems within 300 feet of the Critical Area. 12. Create Stream Eco-Teams Urban/suburban homeowners will be recruited to participate in local teams that adopt local waterways by monitoring and conducting Stream Clean-ups. 13. Restore oyster reefs to reduce turbidity. The committee overseeing WRAS implementation recently released a report showing progress with regard to many of the 13 strategies: Six Years of Corsica River Restoration: 12

17 January 2006 through December Table 2, in the Six-Year report lists an impressive 17 WRAS projects completed thus far with another ten on-going at a total cost of $2,354,111. MARYLAND BIOLOGICAL STREAM SURVEY (MBSS) DATA Between 2000 and 2005, the Maryland Biological Stream Survey analyzed fish, macroinvertebrates, water chemistry and physical habitat at 26 points on nontidal streams within the Corsica River system. This sampling was repeated between 2007 and The purpose was to determine if the many improvements made as a result of the WRAS had a measureable effect on stream health. At first glance Table 3, would seem to indicate a slight decline in the health of fish populations from 2006 to However, the differences are too small and the data too variable to be significant. The lack of improvement should not be viewed as a direct reflection of restoration effectiveness. As will be seen in the next paragraph, it can take quite some time for the benefits of restoration efforts to translate into healthier ecosystems. Table 3: Fish Health Comparison Health Rating Good 30% 29% Fair 50% 46% Poor 20% 25% The most dramatic, fully implemented restoration practice thus far has been upgrading the Centreville WWTP to a better treatment system (Sequential Batch Reactor) and applying the effluent to land via spray-irrigation. Previously, all of the effluent was discharged into Gravel Run near the head of tide. These tidal-nontidal zones are difficult to assess, which likely accounts for a lack of sampling stations above and below the discharge point. The other biggest change is a substantial increase in winter cover crops which should cause nitrogen levels to decline over time. In general, most of the nitrogen entering streams like those of the Corsica drainage comes in with groundwater seeping from springs, wetlands or directly into the channel. Only a small portion is transported in surface runoff. Winter cover crops substantially reduce the amount of nitrogen entering groundwater and transported in surface (cropfield) runoff. But we will not see the full benefits in Corsica River tributaries until enough post-cover crop rainfall percolates through the soil to reach a seep, spring or stream channel. In the Corsica watershed, the depth from the surface of a cropfield to the water table ranges from five- to fifteen feet. 4 It can take three years for rainfall to percolate 2 Six Years of Corsica River Restoration: January 2006 through December 2011, published 2012, available online at: 3 The results were reported in Status and trends in biological condition, water quality, and habitat conditions in the Corsica River watershed ( ), published 2010, available online at: ftp://dnrftp.dnr.state.md.us/public/outgoing/ccws/corsicariverinitiative/mbss_2010_corsica_rpt.pdf 4 Subsurface Nitrate Levels in the Corsica River Watershed: Cover Crop Implementation Results, published 2006, available online at: ftp://dnrftp.dnr.state.md.us/public/outgoing/ccws/corsicariverinitiative/staver_nitrate%20after%20cover%20crop.pdf 13

18 vertically from the soil surface to the water table. 5 In the adjoining German Branch watershed it takes an average of 18 years for water to flow from a cropfield surface to a point of discharge (seep, spring, wetland, channel or shoreline). 6 In other words, it could be a couple of decades before we start seeing noticeable improvements in the portion of the Corsica River ecosystem affected by cropfield releases. The MBSS researchers found that nitrogen levels were higher in subwatersheds dominated by agricultural or urban land uses. Increasing percentages of forest in a watershed was correlated with healthier fish populations and lower nutrient levels. The researchers recommended increasing riparian (streamside) buffers and the extent of forest within the watershed. In the adjoining German Branch watershed DNR biologists found that macroinvertebrate and fish populations were controlled more by habitat than nutrient concentrations. 7 The researchers who sampled the Corsica system in the early part of the decade noted that fish populations were dominated by species preferring sand or mud habitats. 8 More diverse and healthier fish populations were associated with more stable habitats containing a larger amount of woody material, gravel and other stable stream beds. 9 MBSS found several nitrogen hot-spots within the Corsica River watershed. The researchers cited USEPA studies showing that in the Mid-Atlantic region natural total nitrogen levels tend to be below 0.87 milligrams per liter (mg/l). The corresponding value for total phosphorus is mg/l. The researchers also noted that the Maryland Department of Natural Resources (DNR) considers a total nitrogen value greater than 7.0 mg/l to be highly elevated with 0.07 mg/l being the corresponding threshold for total phosphorus. 5 Subsurface Nitrate Levels in the Corsica River Watershed: Cover Crop Implementation Results, published 2006, available online at: ftp://dnrftp.dnr.state.md.us/public/outgoing/ccws/corsicariverinitiative/staver_nitrate%20after%20cover%20cr op.pdf 6 An Ecological Assessment of the Corsica River Estuary and Watershed, published 2009, available online at: 7 German Branch Targeted Watershed Project Biotic and Water Quality Monitoring Evaluation Report 1990 Through 1995, published 1997, available online at: 8 Report on Nutrient Synoptic Surveys in the Corsica River Watershed, Queen Anne s County, Maryland, April 2003 as part of the Watershed Restoration Action Strategy, published 2003, Watershed Services, Maryland Department of Natural Resources, 580 Taylor Avenue, Annapolis, MD Status and trends in biological condition, water quality, and habitat conditions in the Corsica River watershed ( ), published 2010, available online at: ftp://dnrftp.dnr.state.md.us/public/outgoing/ccws/corsicariverinitiative/mbss_2010_corsica_rpt.pdf 14

19 The MBSS researchers found that total nitrogen was extremely high at five stream sampling points. One of these hot-spots was in an area dominated by urban and agricultural land uses. The other four were in agricultural areas. The researchers recommended: Knowing where nutrient levels are elevated, sub-watershed specific nutrient reductions plans need to be established. Expanded cover crop planting, wider vegetated buffer strips, or improved stormwater management should be considered within these small drainages. In the 2006 report Restoration & Enhancement Opportunities for the Corsica River Watershed, 10 DNR recommended focusing on hydric (wetland) soils previously converted to farming as the first place to expand riparian buffers, particularly where these soils abut existing forest, floodplains or streams. It appears though that most of the hydric soils in the Corsica watershed are in forest, based upon data available through the USDA Web Soil Survey GIS site. 11 Researchers at the Beltsville Agricultural Research Center (BARC) found that about half the nitrogen entered an agricultural stream along 10% of its length. 12 The BARC researchers called these sections critical areas and theorized that concentrating Best Management Practices (BMPs) at areas draining to these points may be a far more cost-effective approach for reducing nutrient inputs. I understand that MDE and others are looking into similar approaches to identify nutrient critical areas within the Corsica system. ECOLOGICAL ASSESSMENT In 2009, the University of Maryland Center for Environmental Science published an assessment of all available Corsica River data and the implications for ecosystem health. 13 The researchers concluded River quality remains impaired due to excessive nutrient concentrations which cause algae populations to proliferate which, in turn, contributes to reduced water clarity and dissolved oxygen deficiencies. Poor water clarity precludes the return of submerged aquatic vegetation and beneficial bottom-dwelling algae. Dissolved oxygen levels have fallen below that needed for a healthy estuary (5.0 mg/l) and have led to fish kills in recent years. Water quality is poorest at the head of the River and improves as one moves towards the Chester River. 10 Restoration & Enhancement Opportunities for the Corsica River Watershed (undated) is available online at: 11 See: 12 Variations in Base-flow Nitrate Flux in a First-order Stream and Riparian Zone, published 2008, available online at: 13 An Ecological Assessment of the Corsica River Estuary and Watershed, published 2009, available online at: 15

20 Table 4, presents updated nutrient loadings for the Corsica River system from the 2009 assessment. When converted to pounds per year the nutrient loads in Table 4 become 261,668 and 36,085 respectively for nitrogen and phosphorus. The year 2000 MDE TMDL called for reducing nitrogen loading to 287,670 pounds/yr and 22,244 pounds/yr for phosphorus. At first glance one might assume the nitrogen TMDL has been met and now we only need focus on phosphorus. Unfortunately this is not the case. Table 4: Nutrient Sources Assessment SOURCE LOADING (kilograms/month) PERCENT Nitrogen Phosphorus Nitrogen Phosphorus Agriculture 8,099 1, % 73.5% Developed Areas 1, % 25.3% Direct Atmospheric Deposition 452 ~0 4.6% 0.0% Centreville WWTP % 1.2% Septic Leachate 149 ~0 1.5% 0.0% Total 9,891 1, % 100.0% In the decade since MDE drafted the TMDL, water quality modeling science has improved dramatically. Because of this and a number of other changes the target established by the 2000 MDE TMDL may no longer be applicable. In fact, the scientists who compiled the 2009 ecological assessment concluded that the nitrogen loads presented in Table 4 must be reduced by 50% to restore the Corsica River to a condition where submerged aquatic vegetation, benthic algae, fish populations and human uses can be fully restored. One of the most noticeable early signs of success in achieving this goal would be that water clarity would double or triple throughout the River, with the bottom visible to a depth of maybe three feet. This would lead to a greater abundance of fish, shellfish and other organisms. In fact, conditions would return which have not existed in the Corsica system for 50 years. The ecological assessment noted the substantial nutrient load reduction achieved by upgrading the Centreville Wastewater Treatment Plant (WWTP). The scientists suggested three actions to achieve the 50% reduction in nutrient loads: maximize the use of winter cover crops on half of all agricultural fields; increase the removal of nutrients from runoff generated on developed lands with stormwater Best Management Practices (BMPs); and 16

21 upgrade the existing 160 (of 809) septic systems located near tidal waters for better nitrogen removal. The first action may have been achieved and substantial progress has been made towards the second. More on both later in this report. The WRAS Implementers Group set the goal of upgrading nutrient removal in 30 of the 809 septic systems in the watershed. Thus far 48% of the 30 upgrades have occurred. IMPERVIOUS SURFACES & ESTUARINE HEALTH In 2009, the Maryland Department of Natural Resources (DNR) published a study of the relationship between impervious area, dissolved oxygen and fishery health. 14 The study was conducted in ten Maryland tidal waterways, including the Corsica River. Following are the principle conclusions taken verbatim from this study: The 5 milligram per liter (mg/l) dissolved oxygen (DO) target was almost 3-times more likely to have been observed in bottom waters when impervious surfaces (IS) cover 5% or less of a watershed than when IS was 10-17%; The chance of measuring DO below the 2 mg/l threshold 15 was nearly 3-times greater when IS was 10% or more; In systems with target IS (less than 5%), habitat would generally be considered unimpaired and managing harvest of resident fishes would be effective; Preserving watersheds at or below 5% IS would be a viable fisheries management strategy; Increasingly stringent regulation might compensate for habitat stress as IS increases from 5 to 10%; and Above a 10% IS threshold, habitat stress mounts and successful management by harvest adjustments alone becomes unlikely. According to the DNR study, 4% of the Corsica River watershed was covered by buildings, parking lots, streets and other impervious surfaces as of Given the large areas of developable land within the watershed, it seems likely that Corsica River watershed imperviousness will cross the 5% threshold in the not too distant future. The most intense development would occur within the Town of Centreville and in the growth area designated by Queen Anne s County on lands adjoining the Town. Preserving land through the sale of development rights and other measures would certainly slow the pace at which impervious area is added to the Corsica River watershed. As of 14 Impervious Surface Target and Limit Reference Points for Chesapeake Bay Subestuaries Based on Summer Dissolved Oxygen and Fish Distribution, published 2009, available online at: 15 At 2.0 mg/l of dissolved oxygen conditions become very stressful for most organisms. 17

22 2003, 1,958 acres of the Corsica watershed had been preserved. 16 Presently, about 5,850 acres in the watershed are now preserved 17, which brings the total amount of the watershed preserved to an incredible 23%! Another 7% of the watershed is presently developed and 7% is water or wetlands. So as much as 64% of the watershed could be developed. It is doubtful that the other nine watersheds included in the DNR study have benefitted from as many restoration practices as the Corsica. While it is a given that these practices offset impervious surface impacts, the degree of offset is unknown. Hopefully, monitoring will continue and demonstrate that with the right BMPs a healthy estuary is compatible with impervious area greater than 5%. In 2009, Maryland adopted a new approach to mitigating the impact of impervious surfaces known as Environmental Site Design (ESD). 18 While it is possible that ESD will offset some impervious surface impacts, it would be unwise to assume complete mitigation. ESD is a brand new approach with many uncertainties regarding effectiveness, not the least of which is the strain it will put on presently overtaxed inspection capabilities. Prior to ESD each development project might have two or three stormwater BMPs. With ESD the number may increase ten-fold. How all these BMPs will be inspected and maintained is a very serious unanswered question statewide. As noted in other studies cited above, the DNR researchers found that macroinvertebrate communities were healthier in headwater streams draining agricultural watersheds provided there was extensive use of Best Management Practices (BMPs). As impervious surfaces increased, stream health declined, although retaining generous riparian buffers mitigated the impact somewhat. SUMMARY OF CURRENT CONDITIONS & AUDIT RELEVANCE The tidal portion of the Corsica River is suffering from excessive nutrient and sediment inputs which lowers water clarity and inhibits the growth of submerged aquatic vegetation along with benthic algae, both of which are essential to a healthy ecosystem. The nutrients stimulate excessive surface algal growth which reduces water clarity and leads to severe oxygen depletion. Suspended sediment combines with algae to further reduce water clarity. 16 Corsica River Watershed Characterization, published 2003, available online at: 17 Personal communication with Mr. Frank Di Gialleonardo. 18 To learn more about ESD visit: ceds.org/esd, or Pages/programs/waterprograms/sedimentandstormwater/stormwater_design/index.aspx 18

23 To restore the tidal portion of the Corsica River, the University of Maryland Center for Environmental Science assessment called for reducing nutrient inputs by 50%, which would bring about a 70% reduction in algae and a substantial improvement in water clarity, by: maximizing the use of winter cover crops on half of all agricultural fields; increasing the removal of nutrients from runoff generated on developed lands with stormwater Best Management Practices (BMPs) which may reduce the impact of watershed imperviousness approaching the critical threshold of 5%; and upgrading the existing 160 (of 809) septic systems located near tidal waters for better nitrogen removal. Based on fish and macroinvertebrate sampling, the nontidal portion of the Corsica River system is presently rated fair on a scale of poor, fair and good. The nontidal system consists of three major streams: Gravel Run, Mill Stream Branch, and Three Bridges Branch. Of the three, Gravel Run is slightly better than Three Bridges Branch with Mill Stream Branch slightly poorer. While nutrients tend not to be a significant problem for smaller nontidal streams, these waters do convey nutrients to the tidal river. Researchers have isolated five nitrogen hotspots along these nontidal waterways and hope to identify and correct the cause of elevated levels. The factors cited as degrading the quality of nontidal portions of the Corsica River system include: Lack of riparian buffers; Excessive sediment inputs which degrade habitat by filling pool-riffles, burying woody substrate, lowering stability and variations in velocity-depth; Low percentage of the watershed in forest; and Some nontidal stream segments are presently affected by development which will increase as growth continues in the watershed, though full use of erosion and sediment control, Environmental Site Design and other highly-effective aquatic resource protection measures could substantially reduce the impact. Of course greater use of cover crops could also substantially reduce inputs of sediment and other pollutants to nontidal waters. AUDIT OF REGULATED & OTHER AQUATIC ENHANCEMENT ACTIVITIES Normally a Watershed Audit focuses on activities regulated by existing aquatic resource protection laws. However, agriculture is such an important element in the Corsica River ecosystem that several voluntary aquatic resource enhancement activities were included. Also, there has been a phenomenal amount of voluntary restoration in the Corsica River watershed. Therefore the scope of this Audit has been expanded. WHY SITE NAMES & LOCATIONS ARE NOT GIVEN IN THIS REPORT CEDS seeks to achieve correction of water quality problems through the Equitable Solutions, cooperation first approach. It is only after all reasonable efforts to achieve cooperation are exhausted that CEDS moves on to other approaches. It would be inconsistent with cooperation- 19

24 first to publish the name and location of sites found to be causing more pollution than permitted by clean water laws since we have yet to contact the site owner. However, one facility is named because of commendable action to enhance the Corsica River - the Centreville Wastewater Treatment Plant (WWTP). The exception to the cooperation-first approach are those situations where a pollution problem is on-going, causing substantial aquatic resource impact and additional impact may be imminent. CEDS found several construction sites that had extremely poor erosion and sediment control. It was obvious that at least some of these sites had already damaged Corsica River tributaries and more harm would occur come the next rain. Because of this the sites were referred immediately to the Maryland Department of the Environment. See the next section for further detail. CONSTRUCTION SITE EROSION & SEDIMENT CONTROL Several of the studies cited above noted that sediment is a significant factor degrading the quality of the Corsica River, both the tidal and nontidal portions. In 1996, MDE listed the Corsica River as being impaired by sediment. In the tidal portion excessive sediment inputs fill boating channels and combines with algae to prevent sunlight from reaching river bottom areas that might otherwise support submerged aquatic vegetation. Sediment degrades the quality of nontidal stream habitat by filling in pools, riffles and by burying woody material. On a per acre basis, no other land use within the Corsica River system has the potential to release as much sediment as a construction site. Enough soil can erode from a typical construction site to pollute three miles of downstream waters. 19 Recovery of these polluted waters can take a century. However, with the use of the right protection measures this pollution can be eliminated. And THE most effective protection is to prevent erosion in the first place by covering exposed soil with straw mulch, grass, or other "stabilization" materials. When compared to other measures, like the black silt fence pictured to the right, they simply can't keep enough mud on the site to prevent pollution. In fact, whenever you see exposed soil on a construction site, you can Silt fence and other perimeter controls are far less effective than stabilizing soil with mulch-grass assume pollution will occur come the next rain. This is why the principal Chesapeake Bay watershed states - Maryland, Pennsylvania, and Virginia - require protection of all disturbed construction site soils within 3 to 14 days from when bulldozers and other earth-moving 19 Urbanization and Streams: Studies of Hydrologic Impacts, published 1997, available online at: 20

25 equipment first arrive. However, compliance with this vitally important law is less than 100% in many parts of the Bay watershed. Until we can improve compliance, efforts to restore the Chesapeake Bay and our many other degraded waterways, like the Corsica, will be in jeopardy. The bible on construction site erosion and sediment control is Maryland Standards for Soil Erosion & Sediment Control, published by the Maryland Department of the Environment. 20 MDE just replaced the 1994 edition with a 2011 edition, which becomes effective in seven months (January 9, 2013). Both editions emphasize the need to quickly clear a site of vegetation and bring the site up to rough grade where building can begin. Once grading ceases the entire disturbed area must then be stabilized with an application of mulch and grass seed. The mulch, usually straw, must be sufficiently thick to obscure underlying soils from view. It is only by achieving such a thick cover that straw can prevent erosion come the next rain. Under ideal conditions the first seeding leads to a well established stand of grass, which is defined in the new MDE manual as 95% vegetative groundcover. However, many contractorsdevelopers budget for a single seeding. All too often this first seeding achieves a sparse growth of grass, mulch begins blowing away and the underlying soils erode away with each rain. This is not a problem confined to the Corsica River watershed but is statewide and even Bay-watershed wide. This is why CEDS is urging groups like the Conservancy to educate the public, including the development community, that exposed soil on a construction site means pollution of the nearest waterway come the next rain. If this goal is achieved then people will react to exposed construction site soil with the same indignation triggered by littering or aggressive driving. As this perception spreads the area of exposed construction site soil will diminish through voluntary actions on the part of the development-construction community. Why Does Exposed Soil = Pollution? The answer to this question is simple: Clay. Soil is made up of three particle sizes: sand, silt and clay. Clay is the smallest and the hardest to remove once it has been eroded from the soil surface and entrained in runoff. Sand and coarse silt can be kept on a construction site with silt fence, sediment traps (like that pictured to the right), and other perimeter control Sediment traps capture sand, some silt but little clay 20 See: SoilErosionandSedimentControl/Pages/Programs/WaterPrograms/SedimentandStormwater/erosionsedimentcontrol/i ndex.aspx 21

26 measures. These perimeter measures mostly rely upon settling to remove sediment from runoff. The larger particles settle fairly quickly while days or weeks may be required for clay and finer silt to settle from suspension. So, the most effective way of keeping clay on a construction site is to prevent erosion, which means minimizing the exposure of soil to the erosive force of rainfall and runoff. This, in turn, means protecting soil as quickly as possible following disturbance with a layer of straw mulch, then grass. Road beds and parking lot areas are protected by laying down a layer of stone. Collectively, mulch, grass and stone are known as stabilization measures. One might think that the small size renders clay particles harmless. In some respects the opposite is true. Much of the phosphorus, pesticides, and other pollutants washing from construction sites travel attached to clay particles. Many fish eggs have a slightly sticky coating and clay can adhere so thickly to the egg surface that oxygen flow is blocked suffocating the developing fish embryo. Clay is the most expensive particle to remove from drinking water sources. Clay and other suspended particles are responsible for a large portion of the turbidity which blocks sunlight and has greatly diminished the extent of submerged aquatic vegetation (SAV) throughout the Chesapeake Bay and other Maryland waters. Construction Site Audit CEDS identified five active construction sites within the Corsica River watershed. The most severe problem was found at the Centreville Business Park. Following is the text of a message sent to the Maryland Department of the Environment (MDE) requesting an investigation of conditions found at all five sites. Centreville Business Park: There are two large areas of exposed soil within this site on MD 213 at the south end of Centreville. The southernmost is located behind the Food Lion shopping center. There s a large stockpile of earth about 500 feet to the east of the shopping center. The stockpile is poorly stabilized and eroding severely. While a sediment trap is present between the stockpile and Mill Stream Branch, the trap is full of sediment. At the north end of the Business Park, near some recently completed retail space at the north end of Comet Drive, there s another stockpile next to a large stormwater pond. As with the first pile, this one is poorly stabilized and a large amount of material has been deposited in the pond. Of course Maryland law calls for stabilization of exposed soils once earth-moving activity has halted more than momentarily even if a pond is present. Of particular concern are the clay and fine silt particles which do not settle in ponds and can pose such a threat to the fish spawning in the Corsica system at this time. Stabilization seems the most effective way of keeping these fines onsite and out of Mill Stream Branch. North Brook: This project is located on the east side of MD 213 off Wexford Drive. Throughout the southeast area of this project there are numerous lots which either completely lack stabilization or where mulch-grass is too thin to prevent excessive erosion. There are also a few lots north of Wexford. 22

27 Symphony Woods: As with North Brook, there are also a number of poorly stabilized lots within Symphony Woods. These lots are also in the southeast portion of this project. Ashland Meadows: A single lot is being developed along Ashland Drive, off Tanyard Road. The perimeter silt fence is lying on the ground, no longer functioning. Also the entire lot is exposed soil and should be stabilized. Beech Trail Lane: A single lot is under construction at Tanyard Road and Beech Trail Lane. Much of the lot is exposed soil and should be stabilized. MDE directed correction of the deficiencies noted at the Centreville Business Park. MDE referred the other issues to the Queen Anne s Soil Conservation District which oversees erosion and sediment control on individual lots. The Conservancy is working directly with the District regarding these issues. It appears the severe problem at Centreville Business Park had existed for quite some time. If this is correct then it is likely due to the lack of sufficient inspection staff. The Maryland Department of the Environment (MDE) serves as the erosion and sediment control inspectionenforcement agency with regard to construction activity in nine Maryland counties including Queen Anne s. Statewide, MDE oversees 158,058 regulated entities, of which about 13,000 are construction sites. 21 In fiscal year 2011, MDE inspectors were able to visit only 16% of these construction sites even though State law requires an inspection of each site once every two weeks. 22 MDE inspection capabilities are not likely to increase in the near future. In fact, their inspection staff declined by 6% over the past year. One possible solution is for Queen Anne s County to seek delegation of inspection-enforcement authority as was done by other Eastern Shore counties: Cecil, Dorchester, Kent and Worcester. The Town of Centreville could also seek this authority. CEDS also came across a recent logging operation north of the Corsica River. Observation of the operation was limited to that visible from the road. It appeared that all disturbed soils had been effectively treated with a layer of straw mulch and grass. All in all, the erosion and sediment control care taken at this site was impressive. 21 Annual Enforcement and Compliance Report Fiscal Year 2011, published 2012, available online at: utmde/mde_fy11_enforcementcompliancereport.pdf 22 Biweekly inspections are most important when a construction site is active. See Code of Maryland Regulations (COMAR) D for the biweekly inspection requirement, available online at: 23

28 On-Going Audit Recommendations: Construction Sites In May, CEDS conducted a Watershed Audit workshop on behalf of the Conservancy. A portion of the workshop was devoted to training volunteers in methods for evaluating construction site erosion control quality and encouraging developers-contractors to eliminate exposed soil whenever it appears on a site. This approach has been used quite successfully by the Severn River Association 23 and others. It does not require trespass or the other negatives associated with past efforts. The increased public awareness stemming from this workshop could serve to begin spreading the Exposed Soil=Pollution message and generating the public support needed should Centreville or Queen Anne s County opt for enforcement authority. Conservancy volunteers should then request an opportunity to tour each construction site in the Corsica watershed with the party responsible for erosion and sediment control. The tours should be repeated monthly. EXISTING STORMWATER BEST MANAGEMENT PRACTICES Stormwater BMPs include ponds, sand filters, bioretention, specially designed grass channels, infiltration basins-trenches and other measures intended to reduce downstream flooding, retain pollutants washed from impervious surfaces, maintain groundwater recharge, and minimize the high velocities causing channel erosion. Unlike most Chesapeake Bay watersheds, there are two large categories of stormwater BMPs in the Corsica River watershed: those built as part of past development projects and retrofits installed by the Conservancy, the Town of Centreville, Queen Anne s County and the State Highway Administration. Development Project BMPs As early as 1985, proposed development projects within the Corsica River watershed have been required to use stormwater BMPs. According to a 2010 edition of the Maryland Urban BMP Database 24, there are now 85 BMPs treating runoff from as much as 1,180 acres of developed lands or about two-thirds of all developed lands within the watershed (see Table 5, on the next page). If all BMPs were fully functional they could be keeping 2,543 pounds of nitrogen out of the Corsica River each year along with 480 pounds of phosphorus and 127 tons of solids. The solids are mostly sediment derived from channel erosion caused by the excessive velocity and erosive force of runoff from impervious surfaces. CEDS created a listing of the 85 BMPs located in the Corsica River watershed then plotted the location of each using the coordinates from the database. The plots were made with 2008 Google Earth aerial photos as the base imagery. During this process it was apparent that many of the BMPs either had not been built or the coordinates were inaccurate. The population 23 See a 2012 Thank You letter sent to Elm Street Development posted at: 24 Queen Anne s County stormwater management officials felt that the 2010 database accurately accounted for existing BMPs in the Corsica River watershed. The public can access the BMP database via StormPrint: 24

29 Table 5: Stormwater Best Management Practices Serving Corsica River Watershed Development AVERAGE ACRES POLLUTANT REMOVAL EFFICIENCY POLLUTANTS POTENTIALLY RETAINED TYPE NUMBER YEAR BUILT SERVED Nitrogen Phosphorus Sediment Nitrogen Phosphorus Sediment (pounds) (pounds) (tons) Bioretention % 60% 90% Dry Pond % 10% 10% Extended Detention Pond % 20% 60% Grass Channel % 45% 70% Infiltration Basin % 85% 95% Infiltration Trench % 85% 95% Shallow Marsh Pond % 45% 60% Swales % 60% 90% Underground Storage % 45% 60% Wet Pond % 45% 60% 1, Total 85 1, , Pollutant removal efficiency is based upon in Accounting for Stormwater Wasteload Allocations and Impervious Acres Treated, available online at: Pollutants Potentially Retained is based upon average per acre loading rates times the removal efficiency. Loading rates were obtained from Table 1, in Accounting for Stormwater Wasteload Allocations and Impervious Acres Treated.

30 of 85 facilities was then whittled down to 48 BMPs. On March 13, 2012, CEDS visited and evaluated the 48 BMPs. Table 6, provides a summary of the BMPs evaluated. Of the 48 BMPs, 50% had no obvious defect which would interfere with pollutant removal effectiveness. The other 50% had defects ranging from those causing a modest increase in pollutant releases to those so poorly maintained that pollutant retention is essentially zero. The problem BMPs were referred to Centreville and Queen Anne s County officials. As of the date of this report we have not heard the results of the Town and County evaluation of the problem BMPs. Table 6: Stormwater BMP Audit Findings Type Number Problem Noted Nature of Problem Bioretention 1 1 No mulch which is critical to pollutant removal and preventing failure Dry Pond 2 2 No area to store pollutants or floodwaters Extended-Detention Pond 2 2 Storage loss; piping which could lead to spillway failure Grass Channel 5 2 BMP was dry pond with no storage Infiltration Basin 1 0 Underground Storage 2 0 No manholes or other presence indicators; so facilities could not be evaluated Wet Pond Forebay breached; no wet pool; no pollutant storage area; storage reduced due to sediment-cattails; spillway piping; trees on embankment; dewatering device failure Total Percent of Total 50% About eight miles of US Route 301 is located within the Corsica River watershed. Several stormwater BMPs are visible in the highway median. However, it s too dangerous to 26

31 attempt a closer look on foot. Instead a request was sent to the State Highway Administration for details regarding the number, type and location of BMPs. The SHA response noted three facilities in the watershed: a retention pond, a shallow mar h and a wet extended-detention pond. Inspection and maintenance of stormwater BMPs is a serious issue statewide. Maryland law requires inspection of stormwater BMPs a minimum of once every three years. However, TMDLs-Watershed Implementation Planning requires an annual inspection to gain credit for pollutants retained in filtering practices which maybe our most-effective BMPs. 25 A full-time inspector can evaluate about 800 BMPs per year at a cost of roughly $150 per evaluation. 26 Annual BMP maintenance costs range from $600 to $3500 per BMP depending upon type. 27 In the Corsica watershed BMPs are maintained by the owner, whether that be a government agency, a homeowners association or business. The Maryland General Assembly just passed a bill (HB 987/SB614) establishing a source of funding for stormwater BMPs inspection, maintenance and installation in nine counties, but not Queen Anne s. The Town of Centreville is investigating the possibility of establishing a funding source known as a stormwater utility. Similar programs elsewhere in Maryland and Delaware have been quite successful. Given the number of problems noted at existing stormwater BMPs additional funding is certainly an urgent need. Conservancy s Amazing Retrofit Project The Corsica River Conservancy has accomplished something truly unique among Maryland watershed organizations; perhaps even among all groups nationally. The Conservancy has installed a Rain Garden at one of every five households in the Corsica River watershed! Thus far nearly 370 Rain Gardens have been installed at a cost of $2,000 each for a total investment of $740,000. Funding for the Rain Gardens was provided by the Chesapeake and Atlantic Coastal Bays Trust Fund and the National Fish and Wildlife Foundation (NFWF) administered through the Chesapeake Bay Trust. A Symphony Village Rain Garden Program. 25 See Section 6.7.4, Chesapeake Bay Phase 5 Community Watershed Model, USEPA Chesapeake Bay 26 Based on a 2012 detailed evaluation of BMP inspection in Anne Arundel County. 27 Based on Costs of Stormwater Management Practices In Maryland Counties, published 2011, available at: 20Cost%20Report%20to%20MDE_Final%20Draft_12Oct2011.pdf 27

32 The Conservancy s Rain Gardens are installed in private yards generally downhill of a home or other impervious surfaces. After much trial and error the Conservancy found an approach which makes it easy for homeowners to appreciate Rain Garden benefits and get one of their own. A Conservancy volunteer shows the homeowner photos of a couple of different Rain Garden designs, several of which support flowering plants spring, summer and fall. After making a choice the homeowner selects a location for the 250-square foot Rain Garden. A contractor installs the Rain Garden at no cost to the homeowner. After correcting any installation issues Rain Garden maintenance becomes the homeowner s responsibility. Incredibly, homeowners have been maintaining 97% of all Rain Gardens! Of course there s always room for improvement, even with a project as incredibly successful as this one. Ideally, the surface of a Rain Garden should be depressed 6to 12-inches below the first point where runoff could flow from the facility. This depression serves to storh runoff until it can be treated by soaking through the mulch and planting soil layer. It appears that a number of Rain Gardens lack a surface depression. No doubt significant pollutant retention is occurring but it could be only a fraction of what might be achieved. There would be value in using the CEDS Rain Gage & Float method to monitor a few Rain Gardens to get a handle on treatment volumes. Frankly, the surface storage issue is almost trivial compared to the challenges the Conservancy has overcome to get 20% of all watershed homeowners to embrace a Rain Garden in their yard and to achieve a 97% maintenance rate. But it does provide an important opportunity to substantially reduce pollution inputs to the Corsica. Other Retrofits In addition to the Rain Gardens installed through the Conservancy s efforts, another ten retrofit projects have been completed or soon will be. Most were carried out by the Town of Centreville. This is also an extremely impressive accomplishment. One of these retrofits was for the public library on Commerce Street. This is a fantastic project for helping the public understand the benefits provided by Rain Gardens. However, this Rain Garden treats runoff from 13,000 square feet of impervious area. This Rain Garden should have a minimum storage area of 28

33 813 cubic feet below the first point where runoff could flow from the Garden. 28 With this storage volume the Rain Garden would treat the first inch of runoff from impervious surfaces or 90% of all runoff. It looks like the actual storage area in the library facility may be something less 813 cubic feet. The Rain Gage & Float Method could be used to quickly and inexpensively verify storage volume. Centreville Public Library Rain Garden On-Going Audit Recommendations: Stormwater BMPs The May workshop showed Conservancy volunteers how to evaluate stormwater BMPs for opportunities to enhance pollution retention. Unlike construction sites, stormwater BMPs need not be visited monthly but once a year. At least one Maryland county is considering the possibility of using volunteer inspections to verify pollutant retention for TMDL and Watershed Implementation Plan purposes. This County is also considering the possibility of allowing trained volunteers to perform simple BMP maintenance, like replacing mulch in bioretention- Rain Garden facilities every two years. The Conservancy should monitor several typical Rain Gardens to determine just how much runoff is being treated. If it is substantially less than the first inch from impervious surfaces then consideration should be given to opportunities to create additional storage during future installations and repairs. FOREST CONSERVATION Since the mid-1980s those developing land within a thousand feet of the Corsica and its tidal creeks has been required to retain a portion of each site in forest. With the passage of the Maryland Forest Conservation Act in the early 1990s, this became law in all other portions of the watershed. There is a growing amount of scientific research that sensitive aquatic resources cannot be preserved by just limiting impervious area and using highly-effective BMPs. A minimum amount of forest must also be retained within a watershed. At this point it appears that 28 The recommended storage is based on the 2009 Maryland Stormwater Design Manual which calls for treating a minimum of the first inch of runoff from impervious surfaces. The surface storage area is sized to accommodate 75% of this volume with the remainder stored in the mulch and planting soil layers. 29