WSPC07406 - Laserfiche WebLink

Home Browse Search

36.1--8 OOlGJ6 WATER INFORMATION MANAGEMENT SYSTEM HANDBOOK 4. All of the streams listed in exhibit 1, rows a-I are suitable stations. 5. Lacking available local data, the log-Pearson type III 1.5 years recurrence interval peak discharge Is assumed to equate to bankfull discharge. 6. The log-Pearson type III 1.5 years recurrence interval 7-day low flow is assumed to reasonably approximate baseflow. 7. Watershed area will be determined from USGS 7 1/2 minute (1:24000) quadrangles. Following is the stepwise analysis: Step 1 - The needed data are found in exhibit 1. Step 2 - The 1.5 years recurrence interval peak discharge is identified graphically on the representative station log-Pearson type III peak flow analysis. This value is defined to be bankfull discharge. Similarly, the 1.5 years recurrence interval, 7 day low flow is identified from the log-Pearson type III low flow analysis and is defined to be baseflow discharge. The results of this step are: QBl.5 ~ 135.0 QL1 a 5.4 Step 3 - Using the station data for the representative and all suitable stations a functional relation is developed between drainage area, elevation or other watershed characteristics and the respective values of QBl.5 calculated in step 2: QB1.5 - 8.18 DAO.79 Step 4 - Using maps and/or photos, watershed area, area-weighted mean elevation, or other watershed characteristics variables are measured for the point(s) of quantification (see ex. 1, row n) Step 5 - Using the data from step 4 and the relation developed in step 3, QB1.5 is calculated for the point(s) of quantification (Gold Creek in this example): QB1.5 - 8.l80AO.79 _ 8.18(42.4)0.79 _ 157.9 cfs Step 6 - Proceed to Common Step 1, sec. 36.2, appendix B.