Table 4. Comparison of the December 1964 and February 1996 peak streamflows for the HJA gauged watersheds. When instrument malfunctions have occurred, peaks have historically been estimated using past relationships with peak flows from other similar watersheds.
Gaging |---------------Peak Flow----------------| Return Station Year Day Time Cfs Cfsm Rank Interval¹ Comments WS 1 1964 22 Dec 0500 61.2 165.2 2 22 1996 7 Feb 0320 84.3 227.6 1 44 WS 2 1964 22 Dec 0950 35.0 150.4 2 22 1996 7 Feb 0950 46.0 197.4 1 44 Peak from PG3 recorder WS 3 1964 22 Dec 0900 66.4 169.8 est. 1 44 Debris slide, record estimated 1996 7 Feb 0330 56.5 144.6 est. 2 22 Debris slide, record estimated WS 6 1964 22 Dec 1230 10.1 201.6 est. 1 34 Malfunction, record estimated 1996 7 Feb 0440 10.0 200.4 est. 2 17 Debris filled flume, peak estimated WS 7 1964 22 Dec 1400 11.7 197.7 est. 1 34 Malfunction, record estimated 1996 7 Feb 1025 10.1 170.2 2 17 WS 8 1964 22 Dec 1400 14.3 173.0 est. 1 34 Malfunction, record estimated 1996 7 Feb 1135 13.9 168.4 2 17 WS 9 1964 ------ ---- ---- ----- - --- Gaging Station not established 1996 7 Feb 1030 4.7 142.0 1 26 WS 10 1964 ------ ---- ----- ----- - --- Gaging Station not established 1996 7 Feb 1130 8.7 221.6 est. 1 26 Debris slide, peak estimated Mack Cr 1964 ------ ---- ----- ----- - --- Gaging Station not established 1996 7 Feb 1035 330.2 147.2 1 18 Lookout 1964 22 Dec 1100 6660. 279. 2 --- 1996 7 Feb 1100 8000. 332. est. 1 --- USGS estimate ¹ Weibull plotting position (m/n+1) used, where m = event rank (ie., 1=largest) and n = number of events. Note that the estimated return interval for the 7 Feb storm is constrained by the period of record, which varies from 18 years at Mack Creek to 44 years at WS 2.