Drought Management Strategies and Indices of Northeast Coastal

Plain StatesAndrew Benjamin

University of Delaware

Goals:◦ To investigate Drought Monitoring plans of states

along the coastal plain.

◦ Review literature and identify drought indices that could be used to monitor drought operationally in Delaware.

Drought Management at the State Level

Delaware Drought Index (1982)◦ Adopted by Delaware Drought Committee

◦ Based on 6 month precipitation and average monthly stream flow. One indicators is deficient= semi-deficient month. Both are deficient= deficient month.

Delaware

Drought Conditions◦ Drought Warning- induced by two consecutive

deficient months.◦ Drought (Drought Emergency)- induced by four

consecutive months.

Delaware

A Numerical Indicator of Water Conditions for Northern Delaware ( Jordan and Woodruff, 1982) Water Conditions Index

Compared to the PDSI, the above index is less sensitive to short-term changes in precipitation.

Not dependent on soil moisture values.

Delaware

New Jersey Department of Environmental Protection◦ New Jersey Drought Emergency Plan (1991)

Divided in to 6 drought regions

4 Drought Indicators Precipitation, Streamflow, Groundwater, Resovoirs

Updated weekly under dry conditions, biweekly under normal/wet conditions.

New Jersey

1.) Drought Monitoring Response Plan (2000)

◦ Army Corps of Engineers’ definition of drought:

“Droughts are periods of time when natural or managed water systems do not provide enough water to meet established human and environmental uses because of natural shortfalls in precipitation or stream flow.”

Maryland

◦ Divided into 6 regions (based on county lines).◦ 4 Drought indicators

Precipitation, Streamflow, Groundwater, Reservoir storage

◦ Palmer Drought Severity Index Not used specifically for drought management. Used to observe long term trends of water supplies

in aquifers, reservoirs, and streams.

Maryland

Susquehanna River Basin Drought Coordination Plan (2000)

◦ Palmer Drought Severity Index Drought Watch: -2.00 to -2.99 Drought Warning: -3.00 to -3.99 Drought Emergency: -4.00 and greater

Maryland

Pennsylvania State Water Plan

◦ Indicators Precipitation, streamflow, groundwater, soil moisture,

and reservoir levels.

◦ Member of the Susquehanna River Basin Commission

Pennsylvania

◦ Drought Hazard Profile Defines and highlights potential impacts of Hydrologic and

Agricultural drought Economic, Environmental and Social factors.

◦ New York State Drought Plan (1982; revised 1988) Monitored Monthly Climatological data, reservoir/lake storage, stream flow and

groundwater levels Palmer Drought Index and State Drought Index Used

◦ Stages of Drought Normal, Drought Alert, Drought Warning, Drought

Emergency, Drought Disaster

New York

Drought Assessment and Response Plan (2003)◦ Drought Response Technical Advisory Committee

◦ Drought Indicators Precipitation, stream flow, groundwater, reservoir

storage Indicators compared to percentiles from historical data.

Virginia

Drought Assessment and Response Plan (2003)◦ More response plan then detection plan

◦ Stages Normal, Normal-Dry, Moderate Drought, Severe

Drought, Extreme Drought

North Carolina

Regional Drought Early Warning Systems “Currently, pilot project steering committees are

working to refine the project plans and engage potential partners.”

Coastal Carolinas

States that utilize drought indices as well as monitor drought indicators:◦ Delaware◦ Maryland◦ New York

States that only monitor drought indicators against historical averages:◦ Pennsylvania◦ New Jersey◦ Virginia

Summary

Drought Management Literature in Academia

Zarger, et al, 2011◦ PDSI- Palmer Drought Severity Index

◦ SPI- Standardized Precipitation Index

◦ NDVI- Normalized Difference Vegetation Index

◦ U.S Drought Monitor (USDM)

◦ Deciles- dividing long periods of precipitation data into 10% parts

Operational Indices in Literature

Brown et. al, 2008◦ Vegetation Drought Response Index (VegDRI)-

combines NDVI, SPI and PDSI Can provide near-real time maps of drought severity

Better Resolution than USDM- useful for local planning and mitigation

Operational Indices in Literature

Rhee, Im, and Carbone, 2010◦ Scaled Drought Condition Index (SDCI)

Combines NDVI, LST data, and precipitation data(TRMM)

Highly correlated with PDS, SPI and outperformed Vegetation Health Index (VHI) and NDVI in North and South Carolina.

Operational Indices in Literature

Brown, J.F., Wardlow, B.D., Tadesse, T., Hayes, M.J., and Reed, B.C., 2008. The Vegetation Drought Response Index (VegDRI): A new integrated approach for monitoring drought stress in vegetation. GIScience and Remote Sensing, 45 (1): 16–46.

Heim, R. R., 2002. A Review of twentieth-century drought indices used in the United States. Bulletin of the American Meteorological Society, 83 (8): 1146-1165.

Rhee, J., Im, J., Carbone, G. J., 2010. Monitoring agricultural drought for arid and humid regions using multi-sensor remote sensing data. Remote Sensing of Environment, 114 (12): 2875-2887.

Zarger, A., Sadiq, R., Bahman, N., and Khan, F.I., 2011. A review of drought indices. Environmental Review. 19: 333-349.

References