Watersheds Fish 7380, Dr. e. irwin

Goals Review components of catchments Understand structure and function of watersheds Faunal relations and/or ecological processes Restoration and management: where are the pressure points?

Why do we care? Watersheds provide boundaries for management. Definition is possible: it makes sense to manage on a waters.hed basis versus by political boundaries. Requires all land owners and water users in watershed  multiple-use ecosystems

Definitions Watershed-any sloping land surface that sheds water; more functionally-all land enclosed by a continuous hydraulic drainage divide and lying upslope from a specific point on a stream. USGS-HUCs (define)

Drainage divide

Topology Does a watershed need water to be one?

Evolution of dynamic understanding RCC  Watershed  Landscapes Structure and function of multidimensional systems  ecological processes Human impacts versus natural variation

Anaxagoras of Clazomenenae ( B.C.) “Rivers depend for their existence on the rains and on the waters within the earth, as the earth is hollow, and the water in its cavities”

Function of a watershed=produce water Flow regime Quantity (magnitude and duration) Timing (duration and frequency) Quality-or nutrient budgets Factors that control streamflow Climate Topography Geology Vegetation

Riparian-Upland interactions Most dynamic component of watersheds Diverse areas; based on disturbance and heterogeneity of habitats

Riparian Function Dissipate flood energy Moderate drought Store surface waters Recharge ground water Moderate instream temperatures Reduce erosion Add instream habitat diversity Transport corridors Fish and wildlife Energy and materials Sediment

Riparian-River interactions Size and number of pools LWD, boulders from upslope areas Regulate sediment inputs via riparian vegetation

Riparian - Vegetation Function of climate, soils, topography and land use Controls timing and amount of water yield Controls amount of soil for downstream transport

Example 48 inches of rainfall (P); 1000 acre watershed 50% is realized as streamflow (48 x 0.5 =24 inches) Total volume of water yield/year =2,000 acre feet (24 inches x 1,000 acres x 1 ft/12 inches) Average discharge/year = 2.72 cfs (2,000 acre feet/year x 43,560 ft2/acre-ft x 1yr/365d x 1d/86,400 s)

US precipitation-annual average = 30 inches 4.75 billion acre-feet 3.4 billion (70%) lost to E T 3% lost consumptively, remaining 27% is streamflow In general, the % of precipitation resulting in streamflow increases with increased precipitation. E T is the most constant variable in the water equation. When requirement met, the rest is available for runoff. As elevation increases, runoff increases Water supply problems often are not related to water quantity; timing is important

Channel morphology Strait river channel Meandering river channel 06page01.cfm?chapter_no= page01.cfm?chapter_no=13 Braided river channel

Strait river channel

Braided river channels

Meandering river channels

Name that river…..

Erosion and sediment transport Sediment is a major product of watersheds Important to measure Estimated 80% of WQ degradation results from erosion Sediment interacts strongly with other WQ components Sediment yield is directly affected by land use activities Erosion is removal and sedimentation is deposition

Types of erosion Surface Mass movement Channel cutting Stream power = the rate at which a stream does work

Restore and protect = priority Importance of riparian zones outweighs the minor proportion they comprise in the watershed. National priority: NRC 1992 Broad perspective needed (watershed) Scale? Must identify key ecological processes that historically provided structure and function

Water balance equation P = R + E T + S Where: P = precipitation during time interval t R = total water yield or streamflow at t E T = Evapotranspiration at t S =  storage as t , S approachs zero Rearrange R = P – E T - S

ETET Transpiration and evaporation are difficult to measure Equation for ET

The Etowah Regional Habitat Conservation Plan The unique fish of the Etowah face an uncertain future as rapid development degrades their habitat. Federal regulations to protect the fish can impose costly delays and restrictions on growth. The solution is to develop a regional Habitat Conservation Plan that minimizes the impacts of growth, ensuring long-term environmental and economic health for the region.

Counties: Bartow County Cherokee County Cobb County Dawson County Forsyth County Lumpkin County Paulding County Pickens County Cities: City of Canton City of Cartersville City of Dallas City of Dawsonville City of Emerson City of Holly Springs City of Kennesaw City of Marietta City of Roswell City of Waleska City of Woodstock Partners Other Agencies and Organizations : Atlanta Regional Commission Cherokee County Water & Sewer Authority Chestatee-Chattahoochee Resource Conservation & Development Center Etowah Water & Sewer Authority The Georgia Conservancy Georgia Department of Natural Resources Georgia Land Trust Georgia Mountains Regional Development Center Georgia Regional Transportation Authority Kennesaw State University Lake Allatoona Preservation Authority Limestone Valley Resource Conservation & Development Center Mountain Conservation Trust of Georgia The Nature Conservancy U.S. Army Corps of Engineers U.S. Fish & Wildlife Service University of Georgia Upper Etowah River Alliance