n. RWRCC GEOGRAPHIC INFORMAHON SYSTEM 



A. Histon' of RWRCC Geographic 

 Information S^'Stem 



TTie Compaa Commission purchased its first land 

 management system, a Linear Measurement Set (LMS), in 

 1 982-83. The LMS consisted of an Apple 1 1 computer, color 

 monitor, video camera, light uble, linear measuring tablet 

 and printer. This s>'stem analyzed aerial photography to 

 determine geographic and hydrologic information con- 

 cerning arable and irrigated lands. 



In 1986 it became apparent to the RWRCC staff that 

 the LMS was outdated and that a more accurate system 

 would h)e required to effectively analyze natural resource 

 informadon for the Compaa Commission. After consider- 

 able research, a geographic information hardware/software 

 s\'stem was selected tliat would enhance staff efficiency and 

 fiinctionalit)'. This system has become known as the Re- 

 served Water Rights Compaa Commission Geographic 

 Informadon Svstem (RWRCC-GIS). 



B. GIS Capabilities 



As discussed in Chapter I, Geographic Informadon 

 Systems (GIS) store, retrieve, manipulate and analyze re- 

 source data in a digital format. This type of system enables 

 the RWRCC staff to relate different types of spadal data, to 

 idenufy spatial reladonships, model existing data for the 

 interpretation of "what if..." scenarios and to compare past, 

 present and potential conditions. The GIS can generate 

 maps that provide concise visual representations of geo- 

 graphic information that are required when working in 

 negotiation scenarios. This system also allows modeling and 

 analyzing alternative assumptions before final decisions are 

 made. 



A large amount of data manipulation is required to 

 provide RWRCC memben with the most concise, accurate 

 and up-to-date scenarios for making decisions in the nego- 

 tiation of federal and Indian reserved water rights in Mon- 

 tana. The RWRCC has used a GIS since 1987 to analyze 

 land and water resource information related to federal and 

 Indian reservations. 



The RWRCC-GIS was used to evaluate the reserved 

 water rights for the Northern Cheyenne Reservation. Infor- 

 mation compiled by the RWRCC or received from outside 

 sources and stored in the RWRCC-GIS included polygonal 

 data (such as soils and lakes) , linear dau (roads, streams and 

 canals), and point data (wells, springs and stream gages). 



C. Database 



The database created for the Northern Cheyenne 

 analysis was developed in sections and each section was 

 based on 1 :24,000 base topographic maps. The Northern 

 Cheyenne Indian Reservation encompasses an area of aj>- 

 proxi ma tely 445,000 acres and 27 sectional 1 :24,000 quad- 

 rangles. Mylar maps were used to avoid the amount of 

 distortion that is inherent in paper maps. This sectional 

 design and scale provided easy data accessibility. 



1. GIS Data 



Geographic data compiled for use in Northern Chey- 

 enne negotiations were divided into two categories: (1) data 

 currently available within the RWRCC-GISand (2) data on 

 9-track tape and available through conversion when nec- 

 essary. 



Readily available data were converted or digitized into 

 the GIS for data analysis. The data currently in the 

 RWRCC-GIS pertain to soils, political boundaries and 

 elevation. 



Soils units were previously digitized by the Bureau of 

 Indian Affairs (BIA) using maps compiled by the Soil Con- 

 servation Service (SCS). Although this information was 

 available, die RWRCC did not use it b)ecause the original 

 field sheets were not geometrically correaed before the 

 digitization process. This produced distortion errors that 

 would have limited the accuracy of area calculations needed 

 in a soil analysis of this size and importance. Through 

 discussion with SCS staff members in Bozeman, it was 

 agreed chat SCS would re<ompile the soil map units using 

 topographic and orthophoto quadrangle maps. This 

 recompilation created new soil maps that were then digi- 



