Benchmark

We can perform a hand calculation to check our calculator for a groundwater mound beneath a rectangular recharge area. For this benchmark, we will assume the values in Table 1 to compute the maximum height of the mound:

Table 1. Definition of Benchmark Problem
hydraulic conductivity	0.0864 m/d
specific yield	0.01
initial saturated thickness	10 m
length of recharge area	10 m
width of recharge area	10 m
recharge rate	0.08 m/d
time	10 d

Table 2 shows the results of the successive approximation calculations for the benchmark problem. The quantities b and h_m were computed with equations given with our calculator; the values of S* were obtained by interpolation from tabulated values in Hantush (1967, Table 1). Results for h_m, the maximum height of the mound above the aquifer base, are shown to three digits in keeping with the precision of tabulated S* values used in the computation.

Table 2. Hand Calculation for Benchmark Problem
Iteration	b (m)	S*	hm (m)
1	10	0.0468	13.2
2	11.61	0.0416	13.3
3	11.65	0.0416	13.3

You can easily verify that the calculator on this web site matches the above hand calculation very closely for the benchmark problem (Table 3).

Table 3. Benchmark Comparison
Hand Calculation	Calculator
hm = 13.3 m	hm = 13.3 m