We will have an absolute maximum (or minimum) at provided f(c) is the largest (or smallest) value that the function will ever take on the domain that we are working on. Also, when we say the âdomain we are working onâ this simply means the range of xâs that we have chosen to work with for a given problem.
Thompson's slope is about one percent, so each structure manages a zone of about nine acres. At $500 to $2,000 per structure, the drainage water management structures only added about five to 15 percent to the cost of upgrading the field's century-old drainage system.t $500 to $2,000 per structure, the drainage water management structures only added about five to 15 percent to the cost of upgrading the field's century-old drainage system.
Example: If the cost of installing tile drainage is $500 per acre and the expected annual net cash return in crop returns from tile drainage is $100 per acre, the payback period is 5 years ($500 / $100 = 5 years).ile drainage should be designed so the water table between tile lines can be lowered within 24 hours after a rain to a level that will not cause crop injury. Generally, most field crops are not injured if the water table is lowered to at least six inches below the ground surface in the first 24 hours after a rain.