WSP03609

• File Number: 8407
• Description: Platte River Basin - River Basin General Publications
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 7/11/1984
• Author: Joe Tom Wood
• Title: Tunnel Vision - An Analysis of River Call Data in the South Platte River Basin
• Water Supply Pro - Doc Type: Report/Study

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Next, based on the "cumulative departure from normal"

analysis, Table 2 compares relative drought conditions for

various consecutive-year durations depicted by use of the ten

gages. The thrust of Table 2 seems to be that the 1941-1963

period had more severe drought conditions than did the period of

1964-l981. However, the author detects no great difference in

climatic conditions between the two periods as revealed by preci~

pitation data.

Has Native South Platte Basin St~eamflo~ Inc~eased?

Four 'long-term, background (virgin) streamflow gaging sta-

tions were selected to determine if streamflows in the 1964-1981

periOd have been greater than those in the 1941-l963 period.

These streamflow gages record streamflow from watersheds which

have not ~aterially changed in the 1941-l981 period from a hydro~

logic point of view. These streamflow gages are depicted on

Figure 2 and are listed in Table 3.

The 4ata in Table 3 suggest that the 1941-l963 period was

slightly wetter than the 1964-l98l period. Average streamflows

at each of the four gaging stations were greater in the 1941-1963

period than in the subsequent 1964-1981 period.

Whence COmeth the Light, F~om the Tunnel?

Since climatic factors apparently do not account for the

change in call patterns, it is appropriate to focus on trans-

mountain diversions into the South platte River Basin from 1941

through l~8l, particularly those brought over by the Harold D,

Roberts Tunnel.

Table 4 tabulates the annual transmountain diversions of

waters into the South Platte River Basin for years 1941 through

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