Initial Stakeholder WorkshopState Hazard Mitigation Plan

Hydrologic Impacts

Dr. Richard Palmer, Dr. Ridwan Siddique, and Christina Wu

August 2, 2017

Objective• Determine impacts of climate change

on extreme hydrologic events throughout the Commonwealth

• Establish return periods of interest• Translate the anticipated changes for

future time periods centered around:– 2040 and 2080 compared to 2000 – Present results in easy to understand

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GLOBAL CIRUCLATION MODELS IMPACT OF CLIMATE CHANGE ON EXTREMES

DOWNSCALED METEOROLOGIC DATAHYDROLOGY MODEL

Watersheds in Massachusetts (HUC 10)

Connecticut CoastalConnecticut Merrimack

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Hydrological Modeling Using HL-RDHM

• Used by the National Weather Service River Forecast Center

• Made up of 2 modules:– Rainfall-runoff (SAC-HT)– Snow melting effect (Snow-17)

• Model runs at a resolution of:– 2x2 km2 or– 4x4 km2

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Hydrological Modeling Using HL-RDHM

• Inputs– ~ 15 Regionally downscaled climate projections (i.e. precipitation and

temperature) as previously presented at a daily time scale– Using these 15 different climate models will provide an estimate of uncertainty

on future flood and drought conditions under two changing climate scenarios (RCP4.5 & RCP8.5)

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Hydrological Modeling Using HL-RDHM• Outputs

– Hydrological model will be validated using historical observations

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Example Output

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Watersheds in Massachusetts (HUC 4)

Watersheds in Massachusetts (HUC 8)

GLOBAL CIRUCLATION MODELS WATER RESOURCES SYSTEMS MODEL

DOWNSCALED METEOROLOGIC DATAHYDROLOGY MODEL