Groundwater - Surface Water Interaction and Contaminant Movement Teacher Workshop March 13, 2015 UNC-CH Amy Keyworth NCDENR Division of Water Resources Groundwater - Surface Water Interaction and Contaminant Movement Where water occurs, how we use it, and how it moves Setting of groundwater and its relationship to surface water Groundwater contamination and remediation Division of Water Resources

Exploring Geology by Reynolds Johnson Kelly Morin Carter Acknowledgements/resources Textbook Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Resources http://water.usgs.gov/education.html Google images – USGS losing stream Acknowledgements/resources http://water.usgs.gov/education.html Google images – USGS losing stream

Acknowledgements Christine Blanton Lawson (NCDENR DWR) Evan Kane (NCDENR DWR) Ben Mirus (USGS) Acknowledgements/resources Christine Blanton Lawson (NCDENR DWR) Evan Kane (NCDENR DWR) Ben Mirus (USGS)

Where is the water? Biological water Water in minerals Ocean currents Glaciers Clouds and precipitation Flowing water Lakes Groundwater Oceans Where is the water? Note the groundwater piece Biological water: water in cells and structures of plants Water in minerals

How Does Water Move? How Does Water Move?

How Does Water Move? Air currents Condensation Evaporation Precipitation Runoff Infiltration (recharge) Groundwater discharge Transpiration from plants How Does Water Move? List of the processes Concentrate on groundwater discharge and recharge

How Does Water Move? Air currents Condensation Evaporation Precipitation Runoff Infiltration (recharge) Groundwater discharge Transpiration from plants How Does Water Move? Use all to create a water balance Water Balance Equation – Inputs = Outputs

Distribution of Water EXPLANATION Most of Earth’s water probably originated during the formation of the planet or from comets and other icy celestial objects Most of this water moves to the surface over time, such as when magma releases water vapor during eruptions We don’t know how much is trapped as water molecules in minerals in the crust and the mantle <1% is visible to us as surface water

Estimated Water Age Residence Time Oceans and seas @ 4000 years Lakes and reservoirs @ 10 years Swamps 1-10 years Rivers @ 2 weeks Soil Moisture 2 wks to 1 yr Groundwater 2 wks to 10,000 yrs Icecaps and glaciers 10-1,000 yrs Atmospheric Water @ 10 days Millions Age of water in different parts of Earth Note groundwater Wide range of ages Generally meteoric or from precipitation Slow to recharge especially in deeper confined aquifers Fossil water can be millions of years old Not being recharged Ogallala aquifer – S Dakota to Texas Source: Nace, 1971

Groundwater Age http://en.wikipedia.org/wiki/File:Groundwater_flow.svg This is the kind of aquifer system we have in the coastal plain Groundwater operates differently in the Piedmont and mountains Note groundwater Wide range of ages Generally meteoric or from precipitation Slow to recharge especially in deeper confined aquifers Fossil water can be millions of years old Not being recharged Ogallala aquifer – S Dakota to Texas http://en.wikipedia.org/wiki/File:Groundwater_flow.svg

Water Use in U.S. EXPLANATION Much of the thermoelectric power usage is with saltwater Some water used in irrigation is returned to canals and rivers and some soaks into the ground NOTES Top photograph: Ephrata, Washington What industrial uses are you aware of? How does human use change the water? Temperature Chemistry Waste Bottled vs public water supply P 505 – EPA standards

Groundwater Between Grains Most groundwater in pore spaces between grains and clasts Pores in upper parts generally unsaturated Below, pores saturated with groundwater EXPLANATION By clasts, we mean grains of sand, silt, and clay-sized particles, as well as pebbles, cobbles, and boulders Usually clasts of different sizes are present in sediment (sorting) Top of saturated zone is water table 17.03.a1

How Does Groundwater Accumulate? Evapotranspiration Precipitation Surface runoff Wetlands and lakes How Does Groundwater Accumulate? We’re pretty familiar with the surface processes Rain or snowmelt can evaporate or be captured by plants Water can flow down the surface as runoff Water can accumulate on the surface in wetlands and lakes If you think about how much water is in groundwater you have to consider how it gets there and what happens to it once there. Water can seep into the ground Water can reach the water table and seep down into the saturated zone Below the water table, groundwater can flow if the rocks are have interconnected spaces Infiltration Reach water table and saturated zone Groundwater flow 17.03.b1

Needed for groundwater to flow Change in elevation or pressure (head) Porosity Permeability Needed for groundwater to flow Change in elevation or pressure (head) Porosity Permeability

Porosity: Proportion of Open Space Which of the following have lower porosity and which have higher porosity? High porosity Rounded, sorted clasts do not fit tightly Clay particles do not fit tightly High porosity Lower porosity Porosity: Proportion of Open Space Loose clay – holds a lot of water Fresh granite – tight crystals – little pore space Well-rounded, well-sorted clasts do not fit tightly Poorly sorted, angular clasts fit more tightly Crystals in granite fit tightly Poorly sorted clasts fit more tightly Low porosity

Permeability: Pores Connected So Fluids Flow High permeability Granite with many fractures Loosely cemented gravels Low permeability Permeability: Pores Connected So Fluids Flow What family of rocks has porosity and permeability when it first forms? What family has porosity only after fracturing? Websites – play 2 and 4 Porous volcanic rock with isolated pores Compacted clay (shale)

http://techalive.mtu.edu/meec/module06/Porosity.htm http://techalive.mtu.edu/meec/module06/Permeability.htm http://techalive.mtu.edu/meec/module06/Packing.htm http://techalive.mtu.edu/meec/module04/GroundwaterSpeed.htm Websites – play 2 and 4 http://techalive.mtu.edu/meec/module06/Porosity.htm http://techalive.mtu.edu/meec/module06/Permeability.htm http://techalive.mtu.edu/meec/module06/Packing.htm http://techalive.mtu.edu/meec/module04/GroundwaterSpeed.htm http://techalive.mtu.edu/meec/module04/ContaminationMovement.htm