Envirothon Workshop Aquatic Ecology 1-26-08 George Guillen
Distribution of Surface Water • WATER: Most of the surface water on the Planet located in oceans, • 71% of earth covered by saltwater, 97.2% of the worlds water is in the ocean • Freshwater very rare!
Natural Ground Cover 40% Evapotranspiration Infiltration 10% Runoff 25% Shallow infiltration 25% Deep infiltration Source: U.S. EPA
Groundwater: Different types of aquifers and how each type relates to water quantity and quality
Aquifers - unconfined • Groundwater below a layer of solid rock or clay is said to be in a confined aquifer. The rock or clay is called a confining layer. A well that goes through a confining layer is known as an artesian well. • The groundwater in confined aquifers is usually under pressure. This pressure causes water in an artesian well to rise above the aquifer level.
Aquifers - Unconfined • Water percolates through the soil until the soil is saturated. The top of the saturated zone is called the water table. The water table rises and falls according to the season and the amount of rain that has occurred. Note that bedrock below the saturated zone prevents the water from penetrating more deeply. • An unconfined aquifer lacks a confining layer on the top of the saturated zone. http://groundwater.orst.edu/under/aquifer.html#Confined
Confined aquifer Slow to recharge; recharge time may be in years or decades Less susceptible to pollution Quantity of water greater than unconfined Unconfined aquifer Quick to recharge; recharge time may be in months or even days More susceptible to pollution Quantities of water generally lower than confined aquifers Aquifers
Aquifers - • Unconfined aquifer
Climate – longitudinal gradient, effect on freshwater flows in Texas
References for Water Cycle • Good source for diagrams, terms, and extensive discussion of all the water cycle components. Also simple methods for demonstrating sublimation and transpiration: http://ga.water.usgs.gov/edu/watercyclesummary.html#oceans • Interesting, animated interactive water cycle: www.mrhall.org/science/epawatercycle/epawatercycle.htm • Water cycle activities, 9th grade and lower: www.fi.edu/guide/bond/watercycleact.html • Basic concept of water cycle with a section on human impacts: www.purdue.edu/dp/envirosoft/groundwater/src/cycle.htm
Properties of water - chemical properties A water molecule contains one atom of oxygen bound to two atoms of hydrogen. The hydrogen atoms are "attached" to one side of the oxygen atom, resulting in a water molecule having a positive charge on the side where the hydrogen atoms are and a negative charge on the other side, where the oxygen atom is. Since opposite electrical charges attract, water molecules tend to attract each other, making water kind of "sticky." (If the water molecule here looks familiar, remember that everyone's favorite mouse is mostly water, too).
Properties of water - chemical properties As the right-side diagram shows, the side with the hydrogen atoms (positive charge) attracts the oxygen side (negative charge) of a different water molecule. All these water molecules attracting each other mean they tend to clump together. This is why water drops are, in fact, drops!
Properties of water - physical properties Water is unique in that it is the only natural substance that is found in all three states -- liquid, solid (ice), and gas (steam) -- at the temperatures normally found on Earth.
Properties of water - physical properties • Water freezes at 32 Fahrenheit (F) and boils at 212 F. water's freezing and boiling points are the baseline with which temperature is measured: 0 on the Celsius scale is water's freezing point, and 100 is water's boiling point (at 1 atm, freshwater). • Weight: 62.416 pounds per cubic foot at 32°F • Weight: 61.998 pounds per cubic foot at 100°F • Weight: 8.33 pounds/gallon, 0.036 pounds/cubic inch • Density: 1 gram per cubic centimeter (cc) at 39.2°F,
Fresh water ecosystems – important properties of water • Ice is water in its solid form. Unlike most substances, which are densest in their solid state, ice is less dense than water and thus floats. • If this were not the case, Fresh water lakes and rivers would freeze from the bottom up. Fish could not survive, and it is unlikely that rivers and lakes in northern countries would ever completely thaw. E.g. Read Kurt Vonnegut – “Ice 9”
Unique Properties of Water • Dissolving ability – dissolves more substances in greater quantities than any other common liquid • Presence of dissolved ions in water changes physical properties e.g. freezing points, density
Water and Weather - Oceans • The oceans have a profound influence on climate. They are the world's great heat reservoirs and heat exchangers. • Water has a high specific heat index. The high specific heat index of water also helps regulate the rate at which air changes temperature, which is why the temperature change between seasons is gradual rather than sudden, especially near the oceans.
Worlds Oceans • 80% of Southern Hemisphere. • 61% of Northern Hemisphere.
Unique Properties of Water • Water = Life • Without water life could not have evolved
References for properties of water • http://ga.water.usgs.gov/edu/waterproperties.html • http://www.ec.gc.ca/WATER/en/nature/prop/e_therm.htm
Water Uses • United States Geological Service (USGS) surveys nation wide water use every 5 years. The chart to the right is based on the 2000 survey.
Water Users -References • http://ga.water.usgs.gov/edu/wateruse.html • Estimated use of Water in the United States in 2000: http://ga.water.usgs.gov/edu/wateruse2000.html
What Is a Watershed? A watershed is the area of land that drains to a particular point along a stream Center for Watershed Protection
Watershed Delineation • Can be accomplished using topographic maps, flow occurs at right angles to elevation lines • Now days is usually done with GIS software and programs that examine digital elevation models and generate likely pathways of flow i.e. watershed
Watershed delineation references • City of Richardson, Texas: http://www.cor.net/ • Maps and various publications on water resources in the Trinity River Basin: http://tx.usgs.gov/trin/pubs • TCEQ website • HGAC website • TNRIS website • GLO website • ESRI – ArcGIS website
Types of Waterbodies • Ocean – including major seas, high salinity, tides (35 ppt) • Estuary – where river meets sea, intermediate salinity (0-35 ppt) • Freshwater (usually 0 ppt, but can vary. Measured in conductivity (20-1000, high conductivity >1000 = salts)
Types of Freshwater Waterbodies • Streams • Intermittent • Perennial • Rivers (usually 4th order and above), deeper, warmer, more turbid • Ponds – small lakes (< 5 acres) • Lakes – none in Texas (Caddo Lake only) • Reservoirs – impounded rivers, long and deep, e.g. Lake Houston • Wetlands – shallow, emergent vegetation, high likelihood of drying out annually, adjacent to rivers, oxbows, ponds etc.
Impervious Cover and Storm water Runoff 100% Precipitation over Watershed 25% Source: U.S. EPA and Center for Watershed Protection “Site Planning for Urban Stream Protection”, Dec 1995
Impervious Cover and Storm water Runoff Surface Runoff Generated from a One-Inch Rainstorm One-Acre Open Meadow - 218 cubic feet One-Acre Paved Parking Lot - 3,460 cubic feet Source: U.S. EPA and Center for Watershed Protection “Site Planning for Urban Stream Protection”, Dec 1995
Erosion & sedimentation • Effects of road building • Logging • Grazing
Wetland Functions • Water Quality improvement, • Flood protection • Shoreline erosion control • Fish and Wildlife Habitat and nursery areas • Recreational and aesthetic appreciation, waterfowl hunting, and natural products Protecting wetlands in turn can protect our safety and welfare. www.epa.gov/owow/wetlands/vital/people.html
Wetlands have important filtering capabilities for intercepting surface- water runoff from higher dry land before the runoff reaches open water. As the runoff water passes through, the wetlands retain excess nutrients and some pollutants, and reduce sediment that would clog waterways and affect fish and amphibian egg development. Bolivar Flats, Texas Natural Water Quality Improvement
Wetlands function as natural sponges that trap and slowly release surface water, rain, snowmelt, groundwater and flood waters. Trees, root mats, and other wetland vegetation also slow the speed of flood waters and distribute them more slowly over the floodplain. This combined water storage and braking action lowers flood heights and reduces erosion. Wetlands provide flood protection
Riparian = Edge of Water • Riparian Habitat: Areas adjacent to rivers and streams with a differing density, diversity, and productivity of plant and animal species relative to nearby uplands. • Removal of riparian vegetation increases erosion, reduces shading (increasing instream temperature), and increases surface runoff
REFERENCES American Rivers, Natural Resources Defense Council and Smart Growth America, 2002, Paving Our Way to Water Shortages: How Sprawl Aggravates the Effects of Drought Center for Watershed Protection, October 1998, Rapid Watershed Planning Handbook: A Comprehensive Guide for Managing Urbanizing Watersheds Center for Watershed Protection, December 1995, Site Planning for Urban Stream Protection North Carolina Stream Restoration Institute and North Carolina Sea Grant, Stream Restoration: A Natural Channel Design Handbook North Central Texas Council of Governments, www.dfwinfo.com/forecast University of Virginia, July 2002, A Stream Corridor Protection Strategy for Local Governments, http://www.virginia.edu/~envneg/IEN_home/htm. US Department of Agriculture/Soil Conservation Service, Agricultural Handbook 296, USGPO, Washington, D.C. US Department of Agriculture/Soil Conservation Service, 1981, Land Resource Regions and Major Land Resource Areas of the United States, USGPO, Washington, D.C. US Department of Agriculture/Soil Conservation Service, National Resources Inventory, www.usda/nrcs.gov/technical/NRI U.S. EPA, 2005, Protecting Water Resources with Smart Growth, Publication EPA 231-R-04-002, www.smartgrowth.org
Water Quality • Water quality is composed of and measured in terms of biological, physical, chemical and aesthetic traits. • Water quality is defined by it’s ability to support a designated use: contact recreation, aquatic life use, fish and shellfish consumption, drinking water source, navigation. • Highest water quality is attained when it meets all these functions.