Environmental Engineering Reference
In-Depth Information
Karst limestone, and crystalline fractured basalt aquifer geologies are can-
didates for aquifer UPHES. As an example, hydraulic conductivities in the
high plains Ogallala aquifer in the central United States generally lie in the
range of 25 to 100 feet per day (0.017 ft/min to 0.07 ft/min or 0.0086 cm/s to
0.036 cm/s) with an average estimated at 51 feet daily (0.035 ft/min or 0.018
cm/s).
16
In addition, the maximum thickness of this aquifer can exceed 700
feet (213.4 meters). Using these ranges, the transmissivities for several cases
are calculated and shown in Table 4.4. The table selects minimum, maxi-
mum, and median values within the above ranges for hydraulic conductivity
and thickness, and an average expected transmissivity is calculated to be 17.4
ft
2
/min (269.4 cm
2
/s). The depth to water and flow yield of a well are impor-
tant parameters to lead the search for a suitable aquifer UPHES site.
Legal Considerations
Before building a UPHES system, a permit is normally required from the
state in which the system will be installed. In addition, several state and
federal regulations relating to water usage, contamination, quality, and land
use must be followed. This section briefly discusses some of the major regu-
lations
17
to consider when planning a UPHES installation.
Tributary ground water is generally considered “water of every natural
stream” and is subject to appropriation and regulation. The basis for this
classification is the hydrological connection of this ground water to sur-
face water. Legally, tributary ground water is generally treated the same as
TABLE 4.4
Transmissivity Averaging Calculations for Ogallala
Aquifer
Hydraulic
Conductivity
[ft/day]
Hydraulic
Conductivity
[ft/min]
Thickness
[ft]
T[ft
2
/min]
25
0.017
100
1.74
25
0.017
400
6.94
25
0.017
700
12.15
50
0.035
100
3.47
50
0.035
400
13.89
50
0.035
700
24.31
75
0.052
100
5.21
75
0.052
400
20.83
75
0.052
700
36.46
100
0.069
100
6.94
100
0.069
400
27.78
100
0.069
700
48.61
Average
17.36
