Chesapeake Bay TMDL and Virginia Watershed Implementation Plan
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The Chesapeake Bay TMDL and Virginia’s Phase 1 Watershed Implementation Plan WEBINAR November 4th, 2010 Brian Benham and Erin Ling, Biological Systems Engineering Jim Pease, Agricultural and Applied Economics Overview • Chesapeake Bay and Bay Watershed statistics • Efforts to clean up the Bay • Total Maximum Daily Load (TMDL) definition and development • Water quality in the Bay • Pollutant sources and loads • Tools used to develop the Bay TMDL • Reducing pollutant loads to the Bay: Implementing the Bay TMDL 2 Chesapeake Bay Watershed • Largest U.S. estuary • 64,000 mi2 watershed; six states and District of Columbia • 10,000 miles of shoreline (longer than west coast) • 14:1 land to water surface ratio • Average depth 21 ft • Over 3,600 species of plants and animals • $750 million contributed annually to local economy from the Bay • Population = 17 million and growing 3 Source: Chesapeake Bay Program Chesapeake Bay TMDL: How we got here • Water quality deterioration and decreased productivity recognized in the 1970s • 1972 Clean Water Act requires TMDLs for impaired waters • 1983 and 1987 Chesapeake Bay Agreements • Acknowledged decline in living resources http://walthubis.blogspot.com/2005/12/chesapeake-bay-fishing.html • Established Chesapeake Bay Program in EPA Region 3 • 1999 lawsuit – EPA commits to bring the Bay and tidal tributaries into compliance with water quality criteria by 2010 or develop TMDL • 2004 – 2006 Tributary Strategies • Outlined implementation activities to reduce N, P, and sediment by river basin • 2009 Executive Order 4 What is a TMDL? • A Total Maximum Daily Load (TMDL) quantifies the amount of a particular pollutant that a waterbody can receive and still meet water quality criteria – “pollution diet” • TMDL = ΣWLA + ΣLA + MOS Where: WLA = waste load allocation (sum of point source loads) LA = load allocation (sum of nonpoint source loads) MOS = margin of safety Portion of the TMDL load that accounts for a lack of knowledge about relationship between pollutant loads and water quality. MOS in Bay TMDL is IMPLICITLY included in WLAs and LAs. • Bay TMDL addresses nutrients (nitrogen and phosphorus) and sediment expressed as total suspended solids (TSS) 5 How is a TMDL developed? Impairment Water quality Designation standards met Clean Water quality standards not met TMDL Assess Development Study Progress Determine target Implementation pollutant loads needed to meet WQ criteria Implementation Planning How many and what type of pollutant control measures are needed to meet target loads? 6 Illustration adapted from original developed by Dr. Robert Brent, James Madison University Bay and tributaries are impaired • “Impaired” = does not meet water quality criteria • 92 impaired tidal segments, 39 are all or in part in VA • EPA is establishing “pollution diets” (TMDLs) for these segments • TMDLs developed for t/content/maps/cbp_28727.pdf • Nitrogen • Phosphorus • Sediment http://www.chesapeakebay.ne So….WHAT’S happening? water quality criteria violated poor water quality, decreased habitat, Bay species out of balance Nitrogen × Chlorophyll a (algal growth) Phosphorus Ø Dissolved Oxygen Sediment Ø Water Clarity/ Submerged Aquatic Vegetation 8 Water quality criteria for Bay and tidal tributaries: Chlorophyll a • Measure of algal growth • Excess nutrients produce algal blooms • block sunlight http://www.deq.state.va.us/info/Potomacalgalbloom. • reduce water clarity html • decaying algae deplete dissolved oxygen http://hamptonroads.com/2009/08/algae-blooms-spreading- chesapeake-bay 9 Water quality criteria for Bay and tidal tributaries: Water clarity/Submerged Aquatic Vegetation (SAV) • Water clarity (visibility of Secchi disc, depth) • Affected by nutrient and sediment loading • Impacts the extent and survival of SAV; important habitat for finfish and shell fish populations http://ian.umces.edu/imagelibrary/displayimage-92-846.html http://www.ncfisheries.net/habitat/chppSAV.html 10 Water quality criteria for Bay and tidal tributaries: Dissolved Oxygen (DO) • Amount of oxygen dissolved in water (mg/L) • Affected by nutrient loading, circulation, water temperature • DO criteria vary by season and species Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll a for the 11 Chesapeake Bay and Its Tidal Tributaries. April 2003. USEPA. Water quality criteria for Bay and tidal tributaries: Dissolved Oxygen (DO) • Amount of oxygen dissolved in water (mg/L) • Affected by nutrient loading, circulation, water temperature • DO criteria vary by season and species • Extremely low DO levels result in “dead zone” Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll a for the 12 Chesapeake Bay and Its Tidal Tributaries. April 2003. USEPA. Water quality criteria for Bay and tidal tributaries Chesapeake Bay Water Quality Indicators % Goal Achievement, 1985-2008 100 Chlorophyll a Dissolved Oxygen 75 Water Clarity 50 25 % Goal Achievement % Goal 0 1985 1989 1993 1997 2001 2005 2009 Source: Chesapeake Bay Program, "Bay Water Quality," www.chesapeakebay.net 13 What are the sources? water quality criteria violated poor water quality, decreased habitat, Bay species out of balance Nitrogen × Chlorophyll a (algal growth) Phosphorus Ø Dissolved Oxygen Sediment Ø Water Clarity/ Submerged Aquatic Vegetation 14 Nitrogen loading to the Bay by source Agriculture - Manure Atmospheric 17% Deposition 27% Agriculture - Chemical Fertilizer 15% Agriculture - Atmospheric Wastewater Deposition Treatment 6% Plants Septic Systems 19% Urban- 4% Suburban Runoff 10% http://www.chesapeakebay.net/status_nitrogensources.aspx?menuitem=19797, last accessed 10/2010, simulated loads using CBWM Phase 4.3 15 Phosphorus loading to the Bay by source Wastewater Treatment Agriculture - Plants Manure 21% 26% Agriculture - Chemical Fertilizer Urban- 19% Suburban Runoff Natural 31% Sources 3% http://www.chesapeakebay.net/status_nitrogensources.aspx?menuitem=19797, last accessed 10/2010, simulated loads using CBWM Phase 4.3 16 Sediment loading to the Bay by source Urban- Suburban Runoff 19% Agriculture 60% Natural Sources 21% http://www.chesapeakebay.net/status_nitrogensources.aspx?menuitem=19797, last accessed 10/2010, simulated loads using CBWM Phase 4.3 17 2009 model estimated base-line loads and 2025 TMDL target loads 2009 2025 NP NP --- million lbs/year --- Delaware 4.2 0.3 2.9 0.3 District of Columbia 3.1 0.1 2.3 0.1 Maryland 52.7 3.4 39.1 2.7 New York 10.9 0.8 8.2 0.5 Pennsylvania 108.3 4.0 76.8 2.7 Virginia 65.8 7.1 53.4 5.4 West Virginia 5.9 0.9 4.7 0.8 247.5 16.6 187.4 12.5 TOTAL 2009 2025 - billion lbs/year - Sediment (TSS) 8.0 6.3 http://www.epa.gov/reg3wapd/pdf/pdf_chesbay/states_N_P_draft_allocations.pdf 18 http://www.pserie.psu.edu/seagrant/ais/watershed/chesapeake.htm Virginia N model-estimated and target loads million lbs/year - 37% Bay Journal July-August 2010; 19 Virginia Watershed Implementation Plan Phase 1: www.deq.virginia.gov/export/sites/default/tmdl/pdf/vatmdlwipdrft.pdf Virginia P model-estimated and target loads 12 11.3 10 8 7.1 5.8 6 5.4 million lbs/year 4 2 - 52% 0 1985 2009 2017 2025 Bay Journal July-August 2010; 20 Virginia Watershed Implementation Plan Phase 1: www.deq.virginia.gov/export/sites/default/tmdl/pdf/vatmdlwipdrft.pdf Virginia N allocation by sector 65.3 58.5 57.2 million lbs/year 2009 data: ftp://ftp.chesapeakebay.net/Modeling/phase5/Phase53_Loads-Acres-BMPs/VA/, “Loads-Acres_VA_083010.xls” 2017 and 2025 data: Virginia Watershed Implementation Plan Phase 1: www.deq.virginia.gov/export/sites/default/tmdl/pdf/vatmdlwipdrft.pdf; addendum Sept 27, 2010. 21 Virginia P allocation by sector 7.1 5.8 5.4 million lbs/year 2009 data: ftp://ftp.chesapeakebay.net/Modeling/phase5/Phase53_Loads-Acres-BMPs/VA/, “Loads-Acres_VA_083010.xls” 2017 and 2025 data: Virginia Watershed Implementation Plan Phase 1: www.deq.virginia.gov/export/sites/default/tmdl/pdf/vatmdlwipdrft.pdf; addendum Sept 27, 2010. 22 Modeling the Chesapeake Bay • The Chesapeake Bay Program uses a suite of models to predict the water quality in the Bay. • The models use Airshed Model mathematical relationships to simulate how the Watershed Bay responds to Model changes in population, land use, and pollution management. Chesapeake Bay Estuary Models 23 Chesapeake Bay Watershed Model (CBWM) County-based input data: Topographic input data: • population • soils • land use • slopes • cropping systems • hydrology • livestock • best management practices (BMPs) Meteorological input data • precipitation • temperature • solar radiation •etc. CBWM outputs (nitrogen, phosphorus, and sediment loads) are inputs to estuary model that is used to simulate water quality and living resources in the Bay. Graphics source: Chesapeake Bay Program 24 CBWM illustration • River reach in each subwatershed receives nutrient and sediment loads from the land uses in that subwatershed and from upstream reaches River/Stream Reach Model outputs flow, Land uses sediment, nitrogen, and phosphorus Graphics source: Chesapeake Bay Program Land uses in the CBWM • Urban • Agricultural • High Density • Alfalfa hay • Pervious and Impervious • Nursery • Low Density • Pasture (w/ and w/o nutrient mgmt) • Pervious and Impervious • Degraded Riparian Pasture • MS4 (permitted) • Hay (w/ and w/o fertilizer) • Bare/Construction • Animal Feeding Operations (AFO) • Forest • Various crops and crop rotations • Wooded • Conventional (high) till (w/ and w/o manure) • Harvested Forest • Conservation (low) till (w/ and w/o manure) • Extractive (active/abandoned) Plus: Point