THE SIMULATING IRAGI MESOPOTAMIAN MARSHLAND with SWAMP II v. 1.01 (Simulated Wetland Applied to Management Problems) by William J. Mitsch, Ph.D. and Li Zhang, Ph.D. Olentangy River Wetland Research Park The Ohio State University Columbus, Ohio USA Introduction A preliminary, easy-to-use STELLA simulation model was developed for the Mesopotamian Marshlands of Southern Iraq. The model includes simple algorithms for site hydrology, water salinity, macrophyte (Phragmites) biomass, and fish (generalized as carp) (Figure 1). The model in principle can be applied to any marsh restoration or management issues in the region. The model is designed to give a first-cut estimation of the effects of marshland restoration approaches on functions related to human use of the marshlands. It simulates the ecosystem for a total of 52 weeks (1 year) and will be extrapolated to cover a longer time, e.g. 10-20 years, when more data are available for model calibration. The model is based on previous models developed by Professor Mitsch and his students at Ohio State University, specifically models developed for wetlands on the Great Lakes (Mitsch and Reeder, 1991), a constructed flow-through wetland in Illinois (Christensen et al., 1994; Wang and Mitsch, 2000), and an aquatic food-chain and hydrology models of a created river-connected wetland in Ohio similar in function to the Mesopotamian Marshlands (Metzker and Mitsch, 1997; Zhang and Mitsch, 2005). These models were referred to as SWAMP (Simulated Wetlands Applied to Management Problems). This current version designed for the Mesopotamian Marshlands is referred to as SWAMP II. The model is written in high-level language STELLA and can be operated by STELLA 8.01 or higher. The software is available from ISEE SYSTEMS at a relatively inexpensive price. Contact ISEE at http://www.hps-inc.com/ Model Parameters The model has several forcing functions and coefficients that are given default values until site-specific data are determined. The model is also developed to include two wetland basins in series with hydrologic connection directly or indirectly to the Tigris or Euphrates Rivers (Figure 2). The important model parameters that can be set include the following:
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Forcing functions related to river flow: pre-dam Tigrisflow of Tigris River prior to dam construction in the 1970s. Units are in m3/week. post-dam Tigrisflow of Tigris River after dam construction in the 1970s. Units are in m3/week. pre-dam Euphratesflow of Euphrates River prior to dam construction in the 1970s. Units are in m3/week. post-dam Euphratesflow of Tigris River after dam construction in the 1970s. Units are in m3/week. Tigris switch; Eu switch Switches for each river that allow selection of Tigris or Euphrates River as source of water. Value can be 1 or 0 and only one river should be given a 1 for each simulated site. flooding factorA measure of the portion river of flow that goes to the marshlands. Scale is 0 (no river water) to 1 (100 % river flow). Forcing functions related to climate and water quality airtempattern of weekly air temperature for study site in C. solarpattern of weekly solar radiation for study site in kcal m-2 wk-1. precippattern of precipitation for study site in m/wk. ET pattern of potential evapotranspiration for study site in m/wk. dissolved oxygenaverage dissolved oxygen, mg/L. (eventually this can be developed as a state variable). Wetland area and population North marsh areaarea of northern marshland, ha North marsh areaarea of southern marshland, ha number of peoplepeople who are living in the study area and utilize the marshland for food and fiber (default = 3,000 people) Model parameters wtempwetland water temperature for region, weekly data in C salinity factormacrophyte growth coefficient (0-1) as a function of salinity (ppt) macrophyte solar effsolar efficiency, conversion of solar energy to energy of macrophyte productivity, kcal/kcal (default = 0.025) macrophyte respmacrophyte respiration coefficient (default = 0.09 wk-1) macrophyte deathmacrophyte death/loss coefficient (variable; seasonal = 0 to 1 wk-1) water level factor N; water level factor Smacrophyte growth as a function of water depth for north and south marshlands fish river inflowcoefficient for fish entry with river flooding (default = 0.05) fish mobilityrelative mobility of fish between marsh basins (default = 1) fish deathdeath coefficient for fish (default = 0.04 wk-1) fishing use coefficient of fishing by human population (default=0.00067 individuals-wk-1) bird usecoefficient for bird harvesting of fish (default = 0.001 wk-1)
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water column prodaverage annual wate...