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....-~. \1>-.3 ", :~;:' ~ ~ ~ ~ .... ~': ,:,:.)'1 \:;:':;' " rate in inches per hc~r. This data, the average infiltration rates for the different soils monitored in the Grand Valley were determined (surface irrigated sites only) and provi~ed in Figure 2; The infiltration rates vary- from a low of 0.17 inches to a high ,of 0~38 inches per hour. In the infiltration rate calculation, the wetted perimeter was not taken into consideration and the data shown in Figure 2 is based on lOOt wetted acreage. In the Grand Valley, it can be. safely assumed that with furrow-irrigation the wetted perimeter is actually less then sot. This !Deans that the appl,ication infiltration rates shown in Figure 2 could be doubled for sites with every row irrigation-to get an estimate of average soil intake rate (a conservative estimate based upon having only half,_ sot, of the soil surface actually wetted). Alternate row irrigation is also fairly common in the Valley, and with this method the wetted- perimeter may be assumed to be about 25t. In alternate row irrigation situation, the application infiltration rates may be multiplied by a factor of four in order to estimate soil intake rate. :'; I,.. : \. . I Infiltration rate for the first irrigation is generally higher for_ annual row crops, but not necessarily so for perennial crops The monitoring data indicates that for most soils, the infiltration rates may be-higher than previously thought. Irrigation M&E-data from 1985 to 1989 als'o indicates this to be true. Therefore, for. salinity IWM planning purposes "infiltration rate planning ranges" based on 1986 to 1990 M&E data have been provided to the field office planners. .These infiltration rate'ranges seem to provide a better estimate of projected deep percolation, flow rate and - irrigation efficiency. The planning infiltration. ranges and average infiltration rates from 1986 to 1990 are provided below. I Ave~ Infiltr.lplanning2 soil Inta~e3 Rates tM&E) Ranges F~ily soil Tvce lin/hrl lin/hrl lin/hrl Billings silty Clay loam 0.20 0.41 - 0.61 0.3/0.4' Fruita clay loam 0.44 0.89 - 1.33 0.40 Genola clay loam 0.31 0.61 - 0.92 0.40 Hanksville silty clay loam 0.21 0.41 0.62 0.30 Mesa clay loam 0.40 0.81 - 1.21 0.40 Ravola clay loam/fvsl 0.26 0.51 0.770.4/0.5 , InfUtrat(an rate. be.sed on _an esthr.ates whh 951 conHOence 'ntervlt; vetted perimeter wea J\Ot hken 'nto consideration. eltlllOtel baled on dati collected f,en 1986 to 1m. ZYetted Irel tlken Into conslderltlon ISO to JJ percent). J Soil Intltl fllllly baled on the Old Solll Guidi , 27