HR: 0800h
AN: H51C-07    [Abstracts]
TI: A Multi-Faceted Approach for the Assessment of the Evolution (1964-2000) of the Tigris- Euphrates Watershed
AU: * Jones, C
EM: christopher.k.jones@wmich.edu
AF: Geosciences, Western Michigan University, United States
AU: Sultan, M
AF: Geosciences, Western Michigan University, United States
AU: Yan, E
AF: Argonne National Lab, Argonne, IL, United States
AU: Hussein, M
AF: U.S. Embassy, Baghdad, Iraq,
AU: Milewski, A
AF: Geosciences, Western Michigan University, United States
AU: Balekai, R
AF: Geosciences, Western Michigan University, United States
AU: Al-Dousari, A
AF: KISR, Safat, Kuwait,
AB: Rising demands on fresh water supplies are leading to water management practices that are altering natural flow systems world-wide. The most devastated of these natural systems is the Tigris-Euphrates watershed that over the past three decades have witnessed the construction of over 60 engineering projects that eliminated seasonal flooding, reduced natural flow (e.g., approx. 20 percent, between 1964-1980) and reduced marshes downstream. We constructed a continuous (1964 to 2000) catchment-based rainfall runoff model for the entire watershed (area: approx. 1,000,000 km2) using the SWAT model to understand the natural flow system, and investigate the impacts of reduced overall flow and the related LCLUC downstream in the marshes. Precipitation was derived from daily and monthly rain gauge data (56 stations) from 1964-1990 and from SSMI data (1990-2000). Soil types were derived from a global soil map (Natural Resources Conservation Service). Spatial extent of drainage basins, reservoir volume, and marshland volume were derived DTED and SRTM data, evaporation on bare soils and ET on vegetated canopy was calculated using the Penman-Monteith method. A modified Soil Conservation Service (SCS) curve number method was adopted to estimate direct runoff using rainfall excess and Channel routing was conducted using the variable storage method. The model was calibrated against stream flow data in Iraq, Turkey, Iran, and Syria (8, 4, 2, 1, gauges, respectively). Our model results show a substantial decrease in the Euphrates river flow and diminished seasonal flooding following the construction (1975) of the Keban in Turkey (Storing capacity: 31 bcm) and the Tabaqa in Syria dams (storing capacity: 11.7 bcm). Average flow (computed at the Syria-Iraq border) was reduced from 32.6 bcm/yr (1964 to 1974) to 23.15 bcm/yr (1975 to 1985). Prior to damming, the monthly flow peaked in May (average flow: 2130 cms) and bottomed in October (average flow: 117 cms). Seasonal variations resulted primarily from melting of snow in the highlands of Turkey, where melting (March-June) contributed approximately 55 percent of the annual flow. Following the construction of the dams, average peak flow was reduced 1037 cms and base flow increased to 582 cms. In contrast, the input of the Tigris River at the Iraqi border has experienced only minor variations from1964 to1990 and the flow pattern remained quite variable (maximum flow in 1972: 28 bcm; minimum flow in 1973: 15 bcm). Much like the Euphrates, the Tigris receives most (approx. 65 percent) of its annual flow at the Iraqi border from snow melt in Turkey. Currently, the calibrated model is being used to evaluate the effects of the projected decease in flow, resulting from the construction of the Ataturk dam in Turkey (storage capacity: 48.7 bcm).
DE: 1804 Catchment
DE: 1808 Dams
DE: 1834 Human impacts
DE: 1847 Modeling
DE: 1855 Remote sensing (1640)
SC: Hydrology [H]
MN: 2007 Joint Assembly