Overview of DEP Climate Change Integrated Modeling Project: Present Activity and Future Goals Watershed Science and Technical Conference West Point, New

Overview of DEP Climate Change Integrated Modeling Project: Present Activity and

Future Goals

Watershed Science and Technical ConferenceWest Point, New York

September 14-15, 2009

Donald C. Pierson, Elliot M. Schneiderman, Mark S. Zion, David Lounsbury, and Donald Kent

Bureau of Water Supply, New York City Department of Environmental Protection

Hampus MarkenstenUpstate Freshwater Institute

Allan Frei, Aavudai Anandhi, and Adao H. MatonseInstitute for Sustainable Cities, City University of New York

New York City Department of Environmental ProtectionBureau of Water Supply

Water Quality

Effects of Climate Change on the New York City Water Supply

• Climate Change is happening and will continue to occur.

• But we don’t know what the effects will be on: – The Quantity of Water Stored in the Water Supply– The Quality of Water Stored in the Reservoir System.

• Speculation is easy. Projections of changes are difficult, and are inherently uncertain.

• The purpose of this project is to move from speculation to projection.

GCM - Emission Scenario

Current Conditions Scenario

65 Year into Future

Scenario

100 Year into Future

ScenarioECHAM-A1B 1981-2000 2046-2065 2081-2100

ECHAM-A2 “ “ “

ECHAM-B1 “ “ “

GISS-A1B 1981-2000 2046-2065 2081-2100

GISS-A2 “ “ “

GISS-B1 “ “ “

NCAR-A1B 1980-1999 2046-2065 2080-2099

NCAR-A2 “ “ “

•GCM/Emission Scenario data obtained from IPCC AR4 (2007)

•For each GCM/Emission Scenario, precipitation and air temperature are compared in control vs. future periods to derive monthly delta change factors.

Climate Change Scenarios

Delta Change Method Applied for 8 GCM/Emission Scenarios



65 Year into Future

Scenario


ScenarioECHAM-A1B 1981-2000 + 2.7 °C + 4.1 °C

ECHAM-A2 “ + 2.1 °C + 4.3 °C

ECHAM-B1 “ + 1.8 °C + 2.8 °C

GISS-A1B 1981-2000 + 1.9 °C + 2.7 °C

GISS-A2 “ + 2.1 °C + 3.4 °C

GISS-B1 “ + 1.3 °C + 1.7 °C

NCAR-A1B 1980-1999 + 2.9 °C + 3.5 °C

NCAR-A2 “ + 3.0 °C + 4.8 °C




Change in Mean Annual Air Temperature (°C)



65 Year into Future

Scenario


ScenarioECHAM-A1B 1981-2000 + 12.8 % + 11.2 %

ECHAM-A2 “ + 9.1 % + 8.9 %

ECHAM-B1 “ + 4.6 % + 11.2 %

GISS-A1B 1981-2000 + 11.3 % + 15.8 %

GISS-A2 “ + 18.3 % + 21.3 %

GISS-B1 “ + 9.5 % + 10.6 %

NCAR-A1B 1980-1999 + 6.9 % + 6.3 %

NCAR-A2 “ + 6.0 % + 13.4 %




Percent Change in Mean Annual Precipitation

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

J F M A M J J A S O N D

-10

-5

0

5

10

15

20

25


GCM Derived Changes in Air Temperature and Precipitation and Watershed Model Derived Projections of Stream flow and Snowpack

Sum of Delaware and Catskill System Watersheds100 Year Forward Scenarios

Mean Air Temperature (oC)

Based on 8 GCM/Emission Scenarios. Upper and lower bars are max and min of these. Box is the range of the remaining 6 scenarios. Bar within box is the median. Line shows baseline run.

Mean Precipitation (cm/day)

0

1

2

3

4

5

6

7

8

9


Mean Snowpack (cm)

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5


Mean Streamflow (cm/day)

min

max

median

87.5 %tile

12.5 %tile

Start With Speculation

Air Temperature• Magnitude• Seasonality

Precipitation• Magnitude• Intensity• Timing

Other Climate Data• Solar Radiation• Humidity• Wind

Potential Climate Change Effects on NYC Water SupplyClimate Forcing

Hydro-thermal Effects• Increased Water Temperature• Reduced Ice Cover• Longer Period of Thermal Stratification• Changes in Reservoir Water level and

Residence Time


Hydrology Effects• Increased Evapotranspiration• Increased Precipitation• Changes in Winter Precipitation, Snow

Accumulation, and Timing of Snowmelt• Changes in Antecedent Conditions• Changes in Partitioning Between Sub-

surface and Surface Runoff• Changes in the Amount and Seasonality

of Stream Flow



Potential Climate Change Effects on NYC Water SupplyHydrology and Hydrodynamics


Residence Time





of Stream Flow



Potential Climate Change Effects on NYC Water SupplyTurbidity

Turbidity Loading Effects• Changes in the Frequency and Magnitude of

Storm Events• Changes in runoff:rainfall response• Changes in Stream Channel Erosion• Changes in Landscape Erosion

Reservoir Turbidity• Changes in the Frequency and Magnitude

of Turbidity Inputs• Changes in the Transport of Turbidity Due

to Changes in Hydrodynamics• Changes in Reservoir Operations• Changes in Alum Use


Residence Time





of Stream Flow



Potential Climate Change Effects on NYC Water SupplyEutrophication

Nutrient Loading Effects• Changes in the Frequency and Magnitude of

Storm Events• Changes in the Timing of Nutrient Loading• Changes in Proportion of Surface Runoff• Changes in Watershed Biogeochemistry

Reservoir Trophic Status• Changes in the Timing and Magnitude of

Nutrient Inputs• Changes in the Nutrient Availability Due to

Changes in Stratification and Mixing• Changes Phytoplankton Growth and

Succession Due to Changes in Water Temperature and Light Extinction

• Changes in Hypolimnetic Oxygen and Nutrients

How to Make Projections

Integrated Modeling System

WatershedModels

(GWLF-VSA,SWAT)

Models


Watershed - Land Use - Soils - Topography - Hydrography - GIS Based - Management

Data

Time Series - Meteorology

- Flows - WQ

Flows WQ Loads

Watershed Models

WatershedModels

(GWLF-VSA,SWAT)

Models

Flows WQ Loads



Data


- Flows - WQ

ReservoirModels

(1D HydrothermalEutrophication,CEQUAL-W2)

ReservoirWQ

Reservoir - Bathymetry - Infrastructure

Watershed and Reservoir Models

Time Series –Historical Reservoir

Operations

WatershedModels

(GWLF-VSA,SWAT)

Models

Flows WQ Loads



Data


- Flows - WQ

ReservoirModels


ReservoirWQ


SystemModel(OASIS)

FlowsOperations

System Performance- Storage- Demand- Spills

Watershed, Reservoir and System Models

Results

Flows

System-Operating Rules-Demand

WatershedModels

(GWLF-VSA,SWAT)

Models

Flows WQ Loads



Data


- Flows - WQ

ReservoirModels


ReservoirWQ


SystemModel(OASIS)

FlowsOperations

Results

Watershed Management

Land Use Changes

Changes

Trophic State

Analysis of Watershed Management and Eutrophication

Flows



Turbidity-Freq / Magnitude-Alum Decisions

WatershedModels

(GWLF-VSA,SWAT)

Models

Flows WQ Loads



Data


- Flows - WQ

ReservoirModels


ReservoirWQ


SystemModel(OASIS)

FlowsOperations

Results


Land Use Changes

Changes

Trophic StateClimate

Change(Delta Change,

SDM,RCM)

Climate Change Analysis – Phase I

Flows



DemandProjections

System Infrastructure

OperatingRules

•Produce preliminary results in 18 months•System Indicators of Water Quantity•Upstream reservoir simulations

•Schoharie – effects on turbidity•Cannonsville – effects on eutrophication

•Use existing models•Develop preliminary model coupling to OASIS•GCM data and simple downscaling

CCIMP Phase I

Watershed ModelGWLF

Water Quantity System Indicators

Reservoir Models1D (Eutrophication)2D (Turbidity)

System Operation ModelOASIS

Climate Data•Historical•GCM Predictions

Simulated Reservoir Operations

Turbidity System Indicators

Eutrophication System Indicators

Historical Reservoir Operations

Phase I Study Areas

• Quantity – Focus on West-Of-Hudson watersheds and reservoirs

Location Map

NYState

NY City

• Turbidity – Focus on Schoharie Reservoir

• Eutrophication – Focus on Cannonsville Reservoir

A. Anandhi et al. Future climate projections of NYC watershed: GCM selection and downscaling.

A. Matonse et al. Climate change impacts on water availability in NYC water supply

M. Zion et al. Potential Impacts of Climate Change on Water Quality in New York City Water Supply System

H. Markensten et al. Climate Change Effects on Phytoplankton Composition in Cannonsville Reservoir

Results Presented Here

Continuation of Phase I •Improved Downscaling•Expanded reservoir simulations

• Catskill System – effects on turbidity• Delaware System – effects on eutrophication

•Expanded system operation modeling• More explicit accounting of EOH and Delaware

River Basin• Explicit Feedback between Water Quality and

Operation – Use of OST

CCIMP Phase II

Watershed ModelExpanded in scope and greater testingGWLFSWATConcepts

Reservoir Models1D (Eutrophication)2D (Turbidity)Expanded in scope and greater testing

Climate Data•Historical•GCM Predictions•Improved Downscaling

Turbidity System Indicators

Eutrophication System Indicators

Additional Tasks •Watershed erosion sediment transport modeling•Forest Modeling•Explicit modeling of watershed biogeochemistry•Model evaluation for climate sensitivity

• What model processes are most sensitive to Climate Change?

• Are these processes adequately represented in models?

Forest Model

Water Quantity System Indicators

System Operation ModelOASIS

Simulated Reservoir Operations Optimization for future climate

Summary• DEP’s system of watershed, reservoir and system operation models are valuable

tools to project potential climate change effects on the NYC Water Supply, and to define the climate mediated processes that will be of greatest importance

• An Initial phase of analysis is nearing completion and results will be presented in the remainder of this session

• Future analysis will make use of improved climate data sets and improved models. New modeling of watershed erosion and forest processes will be undertaken

• Phase I analysis, while a valuable initial step, and the best estimate we can make at this time, can not be used to make definitive climate change predictions

• Modeling improvements and enhancements to improve climate change projections will lead to improvements in our other modeling missions such as evaluation of watershed management programs and management of reservoir turbidity

Aknowledgements

• DEP for funding of CCIMP project as a joint effort with CUNY.

• Columbia University and NASA GISS for support in planning CCIMP, and for initial GCM data

• Outside reviewers of CCIMP project

Extra

WatershedModels

(GWLF-VSA,SWAT)

Models

Flows WQ Loads



Data


- Flows - WQ

ReservoirModels


ReservoirWQ


SystemModel(OASIS)

FlowsOperations

Results


Land Use Changes

Changes

Trophic State


Water Quality Operational Support

Flows



WatershedModels

(GWLF-VSA,SWAT)

Models

Flows WQ Loads



Data


- Flows - WQ

ReservoirModels


ReservoirWQ


SystemModel(OASIS)

FlowsOperations

Results


Land Use Changes

Changes

Trophic State

DemandProjections


Water System Planning

Flows




OperatingRules

WatershedModels

(GWLF-VSA,SWAT)

Models

Flows WQ Loads



Data


- Flows - WQ

ReservoirModels


ReservoirWQ


SystemModel(OASIS)

FlowsOperations

Results


Land Use Changes

Changes

Trophic State

OperatingDecisions

FlowForecasts

Operation Support Tool (OST)

Flows



DemandProjections


OperatingRules

WatershedModels

(GWLF-VSA,SWAT)

Models

Flows WQ Loads



Data


- Flows - WQ

ReservoirModels


ReservoirWQ


SystemModel(OASIS)

FlowsOperations

Results


Land Use Changes

Changes

Trophic State

Climate Change Adaptation - OST

Flows




Climate Change

(Delta Change,SDM,RCM)

DemandProjections


OperatingRules

Climate Change

(Delta Change,SDM,RCM)

WatershedModels

(GWLF-VSA,SWAT)

Models

Flows WQ Loads



Data


- Flows - WQ

ReservoirModels


ReservoirWQ


SystemModel(OASIS)

FlowsOperations

Results


Land Use Changes

Changes

Trophic State

Climate Change Analysis – Phase II

Watershed-Sediment -Nutrients -Ecosystem

Flows




DemandProjections


OperatingRules

Potential Climate Change Effects on NYC Water SupplySystem Operation


Residence Time




of Stream Flow

Nutrient Loading Effects• Changes in the Frequency and Magnitude of

Storm Events• Changes in the Timing of Nutrient Loading• Changes in Proportion of Surface Runoff• Changes in Watershed Biogeochemistry

Reservoir Trophic Status• Changes in the Timing and Magnitude of

Nutrient Inputs• Changes in the Nutrient Availability Due to

Changes in Stratification and Mixing• Changes Phytoplankton Growth and

Succession Due to Changes in Water Temperature and Light Extinction

• Changes in Hypolimnetic Oxygen and Nutrients

Reservoir System Operation• Changes in Water Inputs• Changes in Water Loss (Spill)• Water Quality Related Restrictions on Use• Changes in System Operation

Future Demand

Documents

Overview of DEP Climate Change Integrated Modeling Project: Present Activity and Future Goals Watershed Science and Technical Conference West Point, New