the state would be able to proceed wisely with the allocation of that water. 

 The study which resulted in this series of reports was one of the fruits of 

 that intention. Several other Yellowstone water studies were undertaken 

 during the moratorium at the state and federal levels. Early in 1977, the 

 45th Montana Legislature extended the moratorium to allow more time to con- 

 sider reservations of water for future use in the basin. 



THE STUDY 



The Yellowstone Impact Study, conducted by the Water Resources Division 

 of the Montana Department of Natural Resources and Conservation and financed 

 by the Old West Regional Commission, was designed to evaluate the potential 

 physical, biological, and water use impacts of water withdrawals and water 

 development on the middle and lower reaches of the Yellowstone River Basin in 

 Montana. The study's plan of operation was to project three possible levels 

 of future agricultural, industrial, and muncipal development in the 

 Yellowstone Basin and the streamflow depletions associated with that develop- 

 ment. Impacts on river morphology and water quality were then assessed, 

 and, finally, the impacts of altered streamflow, morphology, and water 

 quality on such factors as migratory birds, furbearers, recreation, and 

 existing water users were analyzed. 



The study began in the fall of 1974. By its conclusion in December of 

 1976, the information generated by the study had already been used for a 

 number of moratorium-related projects—the EIS on reservations of water in 

 the Yellowstone Basin, for example (Montana DNRC 1976). The study resulted 

 in a final report summarizing all aspects of the study and in eleven 

 specialized technical reports: 



Report No. 1 Future Development Projections and Hydrologic Modeling in 

 the Yellowstone River Basin, Montana. 



Report No. 2 The Effect of Altered Streamflow on the Hydrology and 

 Geomorphology of the Yellowstone River Basin, Montana. 



Report No, 3 The Effect of Altered Streamflow on the Water Quality of 

 the Yellowstone River Basin, Montana. 



Report No. 4 The Adequacy of Montana's Regulatory Framework for Water 

 Quality Control 



Report No. 5 Aquatic Invertebrates of the Yellowstone River Basin, 

 Montana. 



Report No. 6 The Effect of Altered Streamflow on Furbearing Mammals of 

 the Yellowstone River Basin, Montana. 



Report No. 7 The Effect of Altered Streamflow on Migratory Birds of the 

 Yellowstone River Basin, Montana. 



