Water Balance, Freshwater Flows, and Precipitation Associated with Climate Change in the Delaware Estuary Watershed Amy L. Shallcross, PE Operations Supervisor, Water Resources Management Branch Delaware River Basin Commission

WHAT DOES DRBC DO? Manages Resources on a Watershed Basis Manages Resources on a Watershed Basis Regulates Water Quality and Quantity Regulates Water Quality and Quantity Plans for Use of Water Resources Plans for Use of Water Resources Coordinates / Facilitates Coordinates / Facilitates Educates about Water Resources Educates about Water Resources

Delaware River Watershed Facts q Nearly 15 million people (about 5% of the U.S. population) rely on the waters of the basin q Drains 13,539 mi², or 0.4 of 1% of the continental U.S. land area q 216 tributary streams q 4 states, 42 counties, 838 municipalities q 25 Congressional Districts

The Delaware River Port Complex (including docking facilities in Pa., N.J., and Del.) is the largest freshwater port in the world.

Delaware Water Gap Region Longest River without a main stem dam East of the Mississippi

Basin Reservoirs Water Supply (only) Water Supply (only) Penn Forest, Wild Creek, Still Creek, Ontelaunee, Green Lane, Geist, Edgar Hoopes, Union Lake, Lake Hopatcong, and Nockamixon Penn Forest, Wild Creek, Still Creek, Ontelaunee, Green Lane, Geist, Edgar Hoopes, Union Lake, Lake Hopatcong, and Nockamixon 48.1 BG 48.1 BG NYC Water Supply and Flow Augmentation NYC Water Supply and Flow Augmentation Neversink, Cannonsville, Pepacton Neversink, Cannonsville, Pepacton BG BG

Photos Courtesy NYC DEP

Basin Reservoirs (continued) Hydropower Hydropower Lake Wallenpaupack and Mongaup System (multiple reservoirs) Lake Wallenpaupack and Mongaup System (multiple reservoirs) 45.1 BG 45.1 BG Multi-purpose and Flood Loss Reduction Multi-purpose and Flood Loss Reduction Prompton, Beltzville, Marsh Creek, Chambers Lake (Hibernia Dam), Blue Marsh, Lake Galena, Francis E. Walter, Jadwin, Merrill Creek Prompton, Beltzville, Marsh Creek, Chambers Lake (Hibernia Dam), Blue Marsh, Lake Galena, Francis E. Walter, Jadwin, Merrill Creek 39.4 BG (WS, WSA) and 71.4 BG Flood Loss Reduction 39.4 BG (WS, WSA) and 71.4 BG Flood Loss Reduction 414. BG WS/WSA/Power and 71.4 Flood Storage 414. BG WS/WSA/Power and 71.4 Flood Storage

What do we know? General agreement in model studies: General agreement in model studies: Temperature (C) +3 to +5 C Temperature (C) +3 to +5 C Precipitation (%) 0 to +20% Precipitation (%) 0 to +20% Runoff (%) -25% to +20% Runoff (%) -25% to +20% Less confidence in regional precipitation/runoff predictions than temperature Less confidence in regional precipitation/runoff predictions than temperature Regardless of sign of precipitation change, significant changes expected in: temperature, annual streamflow cycle, soil moisture, and snowpack. Anticipate more hot days; more variability Regardless of sign of precipitation change, significant changes expected in: temperature, annual streamflow cycle, soil moisture, and snowpack. Anticipate more hot days; more variability

What do we expect? Equal or Increased Precipitation Equal or Increased Precipitation Greater Intensity of Storms Greater Intensity of Storms Increased Temperatures Increased Temperatures Potential for Extended Droughts Potential for Extended Droughts Some Increase in Sea Level Rise Some Increase in Sea Level Rise (0.5 m – 5 m by 2100) (0.5 m – 5 m by 2100)

Uncertainties Will increased precipitation offset increased water loss due to evapotranspiration? Will increased precipitation offset increased water loss due to evapotranspiration? Will more days for groundwater recharge (unfrozen ground) balance soil moisture deficits predicted with higher temperatures? Will more days for groundwater recharge (unfrozen ground) balance soil moisture deficits predicted with higher temperatures? How will vegetative cover change? How will vegetative cover change?

Eastern Plateau, NY > 71 inches Northern, NJ > 59 inches Southern Eastern Piedmont, PA > 55 inches Northern, DE > 44 inches Southern, NJ > 27 inches Pocono Mountains, PA > 65 inches Southern, DE > 17 inches

18’ 22’

Rutgers – Office of State Climatologist

Is it wet? Is it dry?

Source:

Drought of the 1960’s

Potential Impacts – Water Supply Water Supply Water Supply Prolonged Droughts Prolonged Droughts Evapotransporation Evapotransporation Loss of Snow Pack Loss of Snow Pack Salinity – Sea Level Rise Salinity – Sea Level Rise Infrastructure Infrastructure All Coupled with Increasing Demand All Coupled with Increasing Demand

Changes in Snowpack and Timing of Snowmelt There will be less snow in the winter; this affects water supply for many who depend on the melting of snowpack as a water source. The timing of snowmelt may also change, prompting water resource managers to change how water supply reservoirs are managed. There will be less snow in the winter; this affects water supply for many who depend on the melting of snowpack as a water source. The timing of snowmelt may also change, prompting water resource managers to change how water supply reservoirs are managed.

Jeopardize water supply due to increased salinity levels. Both surface water and groundwater withdrawals in the estuary will be affected. Jeopardize water supply due to increased salinity levels. Both surface water and groundwater withdrawals in the estuary will be affected. Increase river flows to push back salt line Increase river flows to push back salt line Increase costs for water purveyors – moving intake pipes upstream or building desalination plants. Increase costs for water purveyors – moving intake pipes upstream or building desalination plants.

Cannonsville Reservoir under normal conditions. Cannonsville Reservoir (6.5% of capacity). Cannonsville Reservoir is located on the West Branch of the Delaware River NYC RESERVOIR STORAGE DECLINES TO RECORD LOWS

Need and Potential Solutions Need – More Upstream Storage and Reduced Demand Need – More Upstream Storage and Reduced Demand Potential Solutions Potential Solutions Better reservoir management Better reservoir management New Reservoirs? New Reservoirs? New Main Stem Reservoirs? New Main Stem Reservoirs? Use old quarries for storage, Aquifer Storage and Recovery, etc. Use old quarries for storage, Aquifer Storage and Recovery, etc. More System Interconnections More System Interconnections Sea Barriers? Sea Barriers?

Potential Impacts Water Supply Water Supply Flooding Flooding Increased Precipitation Increased Precipitation More Intense Storms More Intense Storms More erosion and debris More erosion and debris Non-Tidal River – Old Towns Non-Tidal River – Old Towns Coastal Surge Coastal Surge

Three Major Floods along the Main Stem Delaware River in less than Two Years September 2004 April 2005 June 2006

Need and Potential Solutions Need – Minimizing Flood Damage Need – Minimizing Flood Damage Potential Solutions Potential Solutions Better Stormwater management - Infiltration, Better Stormwater management - Infiltration, Protection of Headwaters, Riverine Buffers Protection of Headwaters, Riverine Buffers Better Land use decisions, LID Better Land use decisions, LID Different Management of Existing Reservoirs Different Management of Existing Reservoirs Raised or New Reservoirs? Raised or New Reservoirs? New Mainstem Reservoir? New Mainstem Reservoir? Moving People from Harm’s Way Moving People from Harm’s Way Flood Warning/ Flood Mapping Flood Warning/ Flood Mapping

Potential Impacts - WQ Water Supply Water Supply Flood Inundation Flood Inundation Water Quality Impacts Water Quality Impacts Temperature Temperature Dissolved Oxygen Dissolved Oxygen Suspended Sediment Suspended Sediment Lower 7 Q 10 for Wastewater Assimilation/TMDLs Lower 7 Q 10 for Wastewater Assimilation/TMDLs Potential Increase in Waterborne Pathogens Potential Increase in Waterborne Pathogens

FECAL COLIFORM IS WAY D O W N and DISSOLVED OXYGEN IS ↑ FROM 2 PPM TO 7!

Needs and Potential Solutions First –Modeling of Scenarios / Impacts First –Modeling of Scenarios / Impacts Issues – Issues – Existing Water Quality Standards Existing Water Quality Standards Anti-Backsliding Rules Anti-Backsliding Rules How to Handle Natural Changes –Tougher Regulation? How to Handle Natural Changes –Tougher Regulation? Should We adapt to CC-caused WQ Changes? Should We adapt to CC-caused WQ Changes?

Potential Impacts - Biological Water Supply Water Supply Flood Inundation Flood Inundation Water Quality Impacts Water Quality Impacts Biological Impacts Biological Impacts Wetlands Inundation/Loss Wetlands Inundation/Loss Change in Spring Thaw Flows Change in Spring Thaw Flows Migratory Patterns Migratory Patterns Vegetation Changes Vegetation Changes Invasive Species Invasive Species

Sea Level Rise - Impacts on the Delaware Estuary Reduce the amount of natural wetlands and marshes, which act as a buffer, helping reduce non- point source pollution and flooding severity. Wetlands are also an important habitat for wildlife, especially migrating birds and fish. Reduce the amount of natural wetlands and marshes, which act as a buffer, helping reduce non- point source pollution and flooding severity. Wetlands are also an important habitat for wildlife, especially migrating birds and fish.

The animals, plants, and forests of the region may shift their habitat and ranges northward due to increased temperatures and potential decrease in water. The animals, plants, and forests of the region may shift their habitat and ranges northward due to increased temperatures and potential decrease in water. Biodiversity among species may also decrease, which can also lead to an increase in invasive species. Biodiversity among species may also decrease, which can also lead to an increase in invasive species.

American shad Already seen: Already seen: earlier bird migration and egg laying, earlier bird migration and egg laying, earlier peak discharges in snow-fed rivers, earlier peak discharges in snow-fed rivers, earlier timing of spring blooms, and earlier timing of spring blooms, and changes in the range and timing of fish migrations in rivers (IPCC 2007) changes in the range and timing of fish migrations in rivers (IPCC 2007)

Photo courtesy of USFWS

Next Steps Prepare for Potential Effects Prepare for Potential Effects Assess Future Demand and Develop Conservation Strategy Assess Future Demand and Develop Conservation Strategy Modify/Create Models with Uncertainty Factors Modify/Create Models with Uncertainty Factors (e.g. drought of record) (e.g. drought of record) Develop Strategic Plans for Droughts, Floods, Sea Level Rise Develop Strategic Plans for Droughts, Floods, Sea Level Rise Adaptation (vs Fighting Change) Adaptation (vs Fighting Change) e.g. –Impact of change in forest species, coldwater to warmwater fishery e.g. –Impact of change in forest species, coldwater to warmwater fishery

Will New Reservoirs be Needed or Will Many Small Changes Be Enough? Need for New Reservoirs and Flood Mitigation Dams? Need for New Reservoirs and Flood Mitigation Dams?or Combination of Combination of Stormwater Infiltration Stormwater Infiltration Protection of Headwaters Protection of Headwaters Stream Corridor Protection Stream Corridor Protection Low Impact Development Low Impact Development Use of Old Quarries Use of Old Quarries Regional Planning Regional Planning Floodplain Regulation Floodplain Regulation

Management Conflicts Need To Manage For Even Greater Extremes Need To Manage For Even Greater Extremes “Stationarity is Dead” – Need for Uncertainty Factor “Stationarity is Dead” – Need for Uncertainty Factor Water Managers like to be Conservative – Water Managers like to be Conservative – Do not gamble with water Do not gamble with water Need More Water Storage for Supply, Instream Flows, Salinity Repulsion and Voids for Flood Mitigation Need More Water Storage for Supply, Instream Flows, Salinity Repulsion and Voids for Flood Mitigation

NEEDS Localized, Downscaled Climate Change Models Localized, Downscaled Climate Change Models Uncertainty Factors for Droughts and Floods Uncertainty Factors for Droughts and Floods Linking Models – CC/Hydrologic/Hydrodynamic/Water Quality Linking Models – CC/Hydrologic/Hydrodynamic/Water Quality Evaluation of Alternatives Effectiveness Evaluation of Alternatives Effectiveness Demand Reduction Demand Reduction Small, Local Solutions to Water Management Small, Local Solutions to Water Management Evaluation of Water Quality Implications Evaluation of Water Quality Implications

Daily Flow Modeling

Time for ACTION !! Integrated Water Management in the Delaware River Basin