Topics in Water Resources :Topics in Water Resources Tom Shields NCST 2000 Fall 2008


General Terms :General Terms Water or Hydrological Cycle The cycle of evaporation and condensation of the earth's water as it evaporates, condenses, precipitates, and returns to the earth Reservoir Any place that water is stored Surface Water Any water at the earth’s surface Ground Water Any water beneath the earth’s surface Confined Unconfined (surficial) Aquifers Porous rock or sediment (especially sandstone) capable of holding and transmitting large quantities of water Water Table The level below which the ground is completely saturate with water. Estuary A partially enclosed coastal body of water, having an open connection with the ocean, where freshwater from inland is mixed with saltwater from the sea.


Geologic Cross-Section:Mountains to Coast :Geologic Cross-Section:Mountains to Coast Because of their different geological makeup, the Mountains and Piedmont depend on different types of water supply from the Coastal Plain. The Piedmont-Blue Ridge Groundwater Region depends mainly on surface water supplies. The Atlantic Coastal Plain Groundwater Region relies mainly on ground water supplies


Water Budget/Hydrological Cycle :Water Budget/Hydrological Cycle Notice how little of the annual rainfall on the Coastal Plain seeps through the ground to recharge the confined ground water supplies that the region depends on.


Coastal Plains Aquifers :Coastal Plains Aquifers Created by alternating layers Porous sand or limestone Confining clay Underlined by bedrock Issues Coning Salt water infiltration


North Carolina’s Coastal Plain Aquifers :North Carolina’s Coastal Plain Aquifers


Basic Aquifer Type and Coning :Basic Aquifer Type and Coning Two types of aquifers Unconfined, or surficial Confined Cones of depression occur when water is drawn from either unconfined or confined aquifers.


Additive Effects of Coning :Additive Effects of Coning A major concern is when the cone of depression from two wells grow enough to intersect. The effect is additive, creating potential problems for both wells.


Castle Hayne Aquifer and Coning :Castle Hayne Aquifer and Coning


Coastal Plains Water Issues :Coastal Plains Water Issues When fresh water is drawn from an aquifer along the Coastal Plain, salt water fills the void.


Piedmont and Mountain Aquifers :Piedmont and Mountain Aquifers Ground water percolates through the unsaturated zone (lifted up in the left picture). The transition between bedrock and softer (partially decomposed) surface rock transmits ground water to a stream. Contamination, as from a landfill, may enter the stream through this runoff.


Dams and Water Management Issues :Dams and Water Management Issues Dams are one way to deal with water management issues, particularly in the Piedmont and Mountains Some of these management issues are: Drought Flood Quantity (shortages) Quality (pollution) Environmental Challenges


Flooding: High Rock Lake :Flooding: High Rock Lake High Rock Lake is near Lexington and Salisbury It flooded in March of 2003


Drought: High Rock Lake :Drought: High Rock Lake This flooding was on the heels of a drought that dried up High Rock Lake in the summer of 2002


Dams: The Good :Dams: The Good Hydroelectric Power Water Supply Reservoir Municipal Industrial & Energy Recreation (Fishing, Boating) Control Floods Regulate stream flow (navigation) Settling Ponds for Contaminants


Dams: The Bad and the Ugly :Dams: The Bad and the Ugly Inundate Farmland Relocation of People Sediment Trap Barriers to Anadromous Fish Temperature Alteration Reduced Stream Flow (Evaporation) Fertility Reduction Downstream Structure Failure!


Other Solutions Besides Dams … :Other Solutions Besides Dams … Desalination Plants Dare & Hyde Counties Reclaimed Water Cary has “Toilet–to–tap” to Water Lawns & Golf Courses Pipelines Virginia Beach from Lake Gaston Purchase from Others Large Municipalities to Small Towns Underground Storage Greenville pumps water back into aquifers when it is available.


Water Quality Issues :Water Quality Issues Sedimentation Industrial Pollution Wastewater Agriculture Biocides Fertilizer Livestock