North Carolina Is Rich in Water, Both Surface Water and Ground Water. Rivers Course Across

Name ______North Carolina’s Water Resources Period ______Date ______Background North Carolina is rich in water, both surface water and ground water. Rivers course across the entire state, tand the Coastal Plain is underlain by water-filled layers of sedimentary rock. While lakes occur all over North Carolina, those in the Mountains and Piedmont are actually reservoirs, made by damming rivers. The Coastal Plain is the only province with naturally occurring lakes, including Lake Mattamuskeet, Lake Phelps, and Lake Waccamaw. Most municipalities in the Mountains and Piedmont use surface water to provide drinking water. This water is often collected in reservoirs made by damming a river. Wells in the Mountains and Piedmont typically have low yields that are suited for private use, but not for an entire town. That’s because the rocks that underlie the Mountains and Piedmont are metamorphic and igneous, which are impermeable – that is, water cannot move in between the mineral grains in the rock. Water can move along fractures in these rocks, however, and it is these water-filled fractures that can supply a family with a well. In the Coastal Plains, however, most municipalities use ground water. The Coastal Plain is underlain by thick layers of sedimentary rocks that hold water in the spaces between individual grains of sediment. Wells drilled into these layers can produce thousands of gallons of water a minute. Rock layers that hold water in large quantities are called aquifers. Rain water enters an aquifer where the aquifer intersects the land surface. North Carolina’s aquifers all tilt so that they are closer to the surface in the west, and deeper to the east. Thus, they receive an inflow of fresh water from the west (see Figure 3). Near the ocean, the aquifers contain salty water. The boundary between the fresh water and salty water can change depending on various conditions. Adding extra freshwater to the system, in the form of heavier-than-usual rainfall, can push the salty water to the east. Pumping too much fresh water out of an aquifer can cause the salty water to be sucked westward. This is called salt water encroachment. Sometimes the salty water can contaminate fresh water wells. In 2002, new North Carolina regulations went into effect to reduce the amount of water that big users (towns, big farms, industries) withdraw from the aquifers. The low relief of the Coastal Plain has led to the formation of many wetlands – areas such as bogs, marshes, and swamps where the soil is often saturated. Wetlands are not only important as wildlife habitats, but also as natural filtration systems. As water moves slowly through a wetland, soil and organisms remove contaminants. Wetlands also help control flooding by soaking up a lot of water during periods of high rainfall.

Part 1 – Aquifers 1. Wells drilled in the Coastal Plain produce much, much more water than wells in the Piedmont or Mountains. Given what you learned in “Get the Ground Water Picture” and the background information, explain why. ______2. North Carolina’s Coastal Plain has many aquifers – rock units that are capable of storing large amounts of water. Maps of some of these aquifers are shown below. Notice that the aquifers vary in thickness and in depth. a. If you drilled a well in central Pender County, what are some of the aquifers you would expect to run into (list them in top to bottom order)? ______b. If you drilled a well in Gates County, would you expect to hit the Castle Hayne aquifer before or after the Upper Cape Fear Aquifer? ______Why? ______Part 2 – Wetlands 1. Wetlands are areas where the soil is often saturated and there may be standing water. Bogs, swamps, and marshes are wetlands. Look at the Wetlands Map below. Given the topography of the Mountains, piedmont, and Coastal Plain, why do you think most of North Carolina’s wetlands are located in the Coastal Plain? ______2. Wetlands store huge amounts of water. When it rains, water soaks in and accumulates in a wetland before moving slowly to the nearest stream. As the water travels through the wetland soils, contaminants are filtered out. By contrast, when rain falls on an area that is not a wetland, the water moves more quickly to a nearby stream, picking up and carrying with it whatever it meets on its way – sediment, fertilizer, animal wastes, or motor oil. Why do you think wetlands might be important for water quality? ______