Water Resources: An Assessment of the Lower Cape Fear Basin

Burrell Montz

Michael Griffin

East Carolina University

Study Area

Mean annual precipitation : 50.92 inches Average temperature: 61.77o F

Problem

• Overall decrease in future water availability in Coastal North Carolina

– Leading to a decrease in the water resource health

• Increased Stress (water availability <1700 m3 PPY)

• Increased Scarcity (water availability <1000 m3 PPY)

– Drivers include:

• Climate Change

• Population Growth

Climate Change

• Hydrologic Cycle – Intensification

• Water Quality issues

– Temperature Increase • Increase in Evapotranspiration (ET)

– Decreased runoff (Mulholland

and Coauthours 1997)

– Precipitation Increase • Change in seasonality (Hurd et al. 1999, Arnell 1999)

– Increases in evaporation likely to exceed increases in precipitation (IPCC 2007)

Anthropogenic Influences

• Land Use – Impervious Surfaces

• Concrete • Asphalt • Buildings

– Influences • Contamination • Soil Moisture

– Alters evapotranspiration

• Increased Demand – Population Growth

• Human Consumption, Energy, Agriculture • Leads to land use change

Downtown Wilmington Impervious Surfaces

±New Hanover County GIS

Population Impacts

(IPCC Fourth Assessment 2007)

Population Growth

Lower Cape Fear Stress Analysis

• Run under varying scenarios of climate, population, and impervious cover.

• Falkenmark indicators: – Stress = Below 1700 m3 per

person per year

– Scarce = Below 1000 m3 per person per year

• Three regions identified

Case Study Scenarios

Scenario Climate Population Variables analyzed Impervious Cover

1 Climate Normals 2000 Census Runoff, Deficit, Falkenmark Indicators Projected 2100 IS Cover

2 Best Case IPCC Prediction 2000 Census Runoff, Deficit, Falkenmark Indicators Projected 2100 IS Cover

3 Mean Case IPCC Prediction 2000 Census Runoff, Deficit, Falkenmark Indicators Projected 2100 IS Cover

4 Worst Case IPCC Prediction 2000 Census Runoff, Deficit, Falkenmark Indicators Projected 2100 IS Cover

5 Climate Normals Projected 2030 Population Falkenmark Indicators Projected 2100 IS Cover

6 Best Case IPCC Prediction Projected 2030 Population Falkenmark Indicators Projected 2100 IS Cover

7 Mean Case IPCC Prediction Projected 2030 Population Falkenmark Indicators Projected 2100 IS Cover

8 Worst Case IPCC Prediction Projected 2030 Population Falkenmark Indicators Projected 2100 IS Cover

9 Mean Case IPCC Prediction 2000 Census Runoff, Deficit, Falkenmark Indicators Current IS Cover

10 Mean Case IPCC Prediction Projected 2030 Population Runoff, Deficit, Falkenmark Indicators Current IS Cover

Falkenmark (2000 population)

Falkenmark (2030 population)

Results

M odel Output Runof f (mm)

Wate rshed ID Scenar io 1 Scenar io 3 Scenar io 9

9 363 .767 320 .131 321 .202

10 363 .414 318 .743 320 .347

11 363 .180 320 .313 319 .778

95 523 .954 426 .610 420 .971

99 523 .467 442 .628 420 .630

100 606 .671 542 .477 523 .735

Falkenmark Water S t ress (m 3 Per person Per Year )

Wate rshed ID Scenar io 1 Scenar io 3 Scenar io 7

9 1538 .591 1354 .028 584 .379

10 2417 .534 2120 .368 1143 .446

11 5543 .306 4889 .024 2885 .231

95 1978 .495 1610 .915 1134 .028

99 1519 .892 1285 .176 777 .749

100 2430 .509 2173 .326 1408 .883

• Climate impacts ( 1 to 3) • Runoff Max 97mm • Falken Max 654

• IS cover impacts (3 to 9) • Similar values

• Population Impacts (1 to 7) • Falken Max 2658

Management Analysis

• Examine local water supply plans (NCDENR)

– Identify at risk areas (i.e. demand surpassing supply)

– Interview local water managers

• Determine their management strategies

• How do they plan to deal with shortages

• Review management options

– Make a case for combined demand and supply management

Local Examples

Conclusions

• Water availability decreasing

• Demand increasing

• Increased stress and scarcity

• Need to explore management options to sustain future populations

• Encourage demand management as well as supply management

Questions?