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and 3-day maximum flows for major stations on the North Fork Gunnison, Gunnison, and Uncompahgre Rivers were analyzed giving consideration to his- torical estimates of flow and estimates of flow for periods of incomplete record. This analysi1 was based on procedures outlined in Water Resources Council Bulletin l7A- . Regionalization of the generalized statistical relationships is briefly discussed below. The statistics used for each station in the analysis are summarized in Appendix B. Kelationships of annual mean peak discharge to drainage area were esti~ mated for the North Fork Gunnison and Gunnison Rivers. The curves for these relationships (Chart 4) compare favorably with those developed for the flood insurance study of Garfield and Mesa Counties. Care must be exer- cised in applying the curves, particularly to tributary drainages, because they represent average relationships for the basin. Standard deviations for snowmelt runoff were similar throughout the basin. For most stations, these values ranged from 0.14 to 0.24 and aver- aged about 0.20. Skew coefficients (being third-moment functions) vary considerably with- in the basin, ranging from -2.20 to 0.81. Information on generalized skew coefficients used to adjust skew coefficients at major gages is included in the following discussion of the development of frequency curves. a. North Fork Gunnison River near Somerset. Records of unregulated flow on the North Fork Gunnison River near Somerset are available for 1934-60. Peak flows for 1922-32 were estimated from peak flow-drainage area relationships developed from the data available for the gage on the North Fork Gunnison River near Paonia (1922-32) and other gages in the basin. Data for the "near Grand Junction" and llbelow Gunnison Tunnel" gages on the Gunnison River (1897-1965 and 1906-65, respectively) were cor- related by the Corps' "Regional Frequency" computer program to estiIJate flows for 1897-1921, 1931, and 1933. The peak flow for the flood of June 1884 was estimated at 12,500 cfs, based on estimates of flow for the "below Gunnison Tunnelll and linear Grand Junctionll gages, and on ratios of peak flows for the "near Somerset" gage to peak flows for the "below Gunnison Tunnel" and "near Grand Junction" gages for other major floods. The esti- mate was then weighted with the recorded and estimated data for the }) "Guidelines for Determining Flood Flow Frequency," revised June 1977. 7