TABLE 19 



AVERAGE TILE DRAIN DISCHARGE, NUTRIENT 

 CONCENTRATIONS AND TOTAL DISSOLVED SOLIDS ACCORDING 

 TO DRAINAGE SITE CLASSES 

 1968 



Drainage : Number : Est imated : Dis charge : Nutrient s (mg/l) 

 Site : of : Tiled : (ac-ft/ - ^o^,^^ . pQ^.p 

 Class : Drains: Acreage ; ac/yr) ; ^"^j - ^^^ 



IB 

 6B 

 IC 



2C 

 4C 

 4D 

 5D 

 IF 

 2F 



TDS 

 (mg/l) 



5,080 

 2,070 

 3,220 

 3,390 

 3,290 

 1,860 

 7,280 

 2,890 

 3,060 



The highest dischsirge according to drainage site classes 

 occurred in the IF and 2F classes, which according to the 

 classification are fine-textured alluvium with dense compact 

 subsoils. These soils which by definition are supposed to 

 be slowly permeable are greatly influenced by surrounding 

 high water table conditions. They are represented by two 

 tile systems in each class. The next highest average 

 dischsirge came from drains located in the IC and 2C classifi- 

 cations, which are located in alluvial and basin rim soils 

 with stratified profiles that allow free lateral movement of 

 water. These last two categories are among the few that are 

 well represented by tiled acreage. The drainage from these 

 classes is considered to be more in line with the quantities 

 expected from highly permeable soils having few restrictions 

 in the subsoil. 



Nutrient concentrations were the highest in drainage compos- 

 ited from the IB and IC classifications, which represented 

 most of the tiled alluvial soils within the study area, and 

 phosphorus was the highest in the 5D class. 



This system of classification, along with additional field 

 exploration, further correlation to tile discharges and 

 nutrient concentrations, could possibly be used to project 

 discharges and nutrient concentrations from areas that are 

 to be tile-drained in the future. 



68 



