2016 S TAT E O F T H E D E L A WA R E INLAND BAYS Presented by The Delaware Center for the Inland Bays PB ACKNOWLEDGEMENTS Report Authors Cardno Delaware Department of Health and Marianne Walch, Emily Seldomridge, Stephanie Briggs Social Services Andrew McGowan, Sally Boswell, and Dan Call Christopher Bason Peter Marsey Delaware Office of State Planning Coordination Lead Editor Delaware Center for the Inland Bays Sally Boswell Brittany Burslem RK&K Robert Collins Jim Eisenhardt This report may be found at Sean Flanagan inlandbays.org. Katie Goerger Sussex County James Hanes, Intern Jayne Ellen Dickerson This project has been funded in part by Steve Maternick Hans Medlarz friends of the Inland Bays, by the Delaware Roy Miller Department of Natural Resources and Molly Struble, Intern Sky Jack Pics Environmental Control, and by the United Focus Group Participants: Susie Ball, TJ Redefer States Environmental Protection Agency Dennis Bartow, Carol Bason, Pat Drizd, under assistance agreements CE09939912 Diane Hansen, Gary Jayne, Pete Keenan, University of Delaware and CE09939913 to the Delaware Center Steve Piron, Ab Ream, Barbara Shamp Scott Andres for the Inland Bays. The contents of this Kevin Brinson document do not necessarily reflect the Delaware Department of Agriculture John Ewart views and policies of the Environmental Christopher Brosch Andrew Homsey Protection Agency, nor does the EPA Robert Coleman Daniel Leathers endorse trade names or recommend the Jimmy Kroon Tye Pettay use of commercial products mentioned in Daniel Woodall Jack Puleo this document. Edward C. Ratledge Delaware Department of Natural Joe Scudlark Design and Production Resources and Environmental Control Bill Ullman Joanne Shipley Michael Bott Jennifer Volk Bruce Cole Ed Whereat GIS Maps John Clark Peter Marsey, Cardno Glenn Davis University of Maryland Baltimore County Andrew Homsey, University of Delaware Kate Fleming Matt Baker Andrew McGowan, CIB Justin Foth Marcia Fox United States Army Corps of Engineers We would like to thank the following Anthony Gonzon Jeffrey Gebert people and organizations for their Michael Greco invaluable assistance with data collection, Edward Hale United States Environmental Protection preparation, analysis, editing, images, Zina Hense Agency and advice for the State of the Bays 2016. Sergio Huerta Finally, without the work of the many Anthony Hummel United States Fish and Wildlife Service dedicated and talented professional Susan Love and volunteer scientists of the Delaware Hassan Mirsajadi United States Geological Survey Department of Natural Resources and Tyler Monteith Judy Denver Environmental Control, the University of Scott Newlin Delaware, and CIB, this report would not Robert Palmer be possible. Alison Rogerson Joe Rogerson The Scientific and Technical Advisory Kathleen Saunders Committee, Delaware Center for the Robert Scarborough Inland Bays Dave Schepens Scott Andres, Chair John Schneider Kari St. Laurent Brittany Sturgis Robin Tyler Sharon Webb David Wolanski Xia Xie Jordan Zimmerman Top cover photo: Marianne Walch Bottom cover photo: Andrew McGowan TABLE OF CONTENTS Executive Summary ........................................................4–5 How We Assess the Health of the Bays .............................. 6 WATERSHED CONDITION .......................................7–18 Human Population Growth ................................................. 8 Land Use Change ........................................................10–11 Impervious Surface Coverage .....................................12–13 Water Quality Buffers on Croplands ................................. 14 Salt Marsh Acreage and Condition .................................. 15 Natural Habitat Protection and Restoration ................16–17 Indian River Inlet Flushing ................................................ 18 MANAGING NUTRIENT POLLUTION .....................20–29 Input of Nutrients from Point Sources .............................. 22 Input of Nutrients from the Atmosphere .......................... 23 Input of Nutrients from Nonpoint Sources ..................24–25 Agricultural Nutrient Management Practices ..............26–27 Septic System Conversion to Central Sewer .................... 28 Stormwater Retrofits ........................................................ 29 WATER QUALITY....................................................30–39 Algae Concentration ........................................................ 31 Concentrations of Nutrients ........................................32–33 Water Clarity ..................................................................... 34 Water Quality Index .......................................................... 35 Dissolved Oxygen Concentration................................36–37 Seaweed Abundance ..................................................38–39 THE INLAND BAYS WATERSHED— QUICK FACTS LIVING RESOURCES ..............................................40–54 Bay Grasses ...................................................................... 41 • The watershed of the Inland Bays is 292 square Eagle and Osprey Nesting ............................................... 42 miles of land that drains to 35 square miles of Hard Clam Landings ......................................................... 43 bays and tidal tributaries. Located within Sussex Winter Waterfowl Counts ............................................44–45 County, Delaware on the mid-Atlantic coastal Box: Oyster Enhancement ................................................ 46 plain of the United States. Blue Crab Abundance ...................................................... 47 • Rehoboth Bay and Indian River Bay are tidally Fish Abundance ...........................................................48–50 connected to the Atlantic Ocean by the Indian Box: Shore-Zone Fish ....................................................... 51 River Inlet. Little Assawoman Bay is connected Number of Fish Kills ......................................................... 52 by the Ocean City Inlet 10 miles to the south in Recreational Fishing Statistics .....................................53–54 Maryland. HUMAN HEALTH RISKS .........................................55–60 • The Bays are shallow, generally less than 7 feet, Bacteria Pollution ........................................................56–57 and have an average tidal range of 3 feet. Approved Shellfish Growing Waters............................58–59 Fish Consumption Advisories ........................................... 60 CLIMATE ................................................................61–66 Carbon Dioxide Concentration and Air Temperature ...... 62 Sea Level Rise ................................................................... 63 Growing Season Length ................................................... 64 Precipitation ..................................................................... 65 Ocean Acidification .......................................................... 66 References ...................................................................68–70 3 Watershed Condition Overview The population of the Inland Bays watershed is growing, and the landscape is rapidly changing from farms and forests to residential and commercial development. Much of the development is concentrated around waterways where its potential impact on water quality is greatest. Since the last report, development increased another 7.8 square miles (11%), replacing agricultural lands, upland forests, and wetlands. With development comes more roads, parking lots and rooftops that generate polluted runoff to the Bays. The watershed as a whole has now exceeded 10% coverage by these impervious surfaces - a tipping point at which water quality has been found to degrade in estuaries. Balancing this is a reduction in the application of fertilizers that occurs when cropland is converted to other land uses. Activities to protect natural habitats in the watershed have nearly stalled since the previous report was published. Saltmarshes are disappearing at higher rates. Funding and incentives for conservation, enhancement of forested buffers, and wetlands protection are needed. The amount of water that moves in and out of the Bays through the Indian River inlet increased (by 11 – 24%) until 2004 and likely continues to improve water quality. What these changes mean long-term for the watershed is uncertain. What is certain as population growth and urbanization continues is that the most effective technology for controlling storm water runoff and treating wastewater will be needed to protect the Bays. WAEXECUTIVETERSHED COND ISUMMARYTION STATUS BAR WATER QUALITY WATERSHED CONDITION MANAGING NUTRIENT POLLUTION STATUS: FAIR TREND: NEGATIVE TREND: POSITIVE TREND: POSITIVE TREND: NEGATIVE Development driven by rapid population The remaining two point sources of Water quality is improving in Little growth is increasing the acreage of nutrients should soon be removed from Assawoman Bay and in open waters near impervious surface coverage, adding to the Bays. Nonpoint source pollution the Indian River Inlet. Algae and seaweed urban pollution sources, and stressing remains above healthy limits. Septic blooms have improved in some areas, but habitats. Agricultural pollution is conversions to central sewer have tributaries and canals are still murky and decreasing as land uses change. Increased exceeded goals set in the Pollution oxygen-starved. flushing at the inlet has improved water Control Strategy, but other management quality in open