Geology Reference
In-Depth Information
QUESTIONS 15, PART A
1.
Using the data in Table 15.1, construct a water-table map
(Figure 15.1). Begin by transferring the water-table eleva-
tions from Table 15.1 to the appropriate test hole locations in
Figure 15.1. Then contour the water-surface elevations using
a contour interval of 2 feet. The contours should roughly
parallel the 864-feet contour already drawn.
4.
What is the gradient from pond C to Saunders Creek? ft/ft.
5.
Calculate the velocity of groundwater moving from pond
C to the Olentangy River and from pond C to Saunders
Creek using the following formula and the data given earlier
in this exercise on the hydraulic characteristics of the uncon-
solidated material.
v = {KI)/(n
e
)
2.
Draw several flow lines originating at the brine holding
ponds to the most likely area of groundwater discharge.
Remember that during dry weather streams flow only
because groundwater discharges into them.
where
v =
velocity (ft/day),
K =
hydraulic conductivity
(ft/day) I = gradient, (ft/ft), and n
e
= effective porosity
(% as a decimal)
a. The velocity of groundwater from pond C to the Olen-
tangy River is about
ft/day.
3.
What is the gradient from pond C to the Olentangy River?
ft/ft.
TABLE 15.1 Chloride Content of Wells and Water-Table Elevation in the Delaware Area
Well No.
Water-Table Elevation (March 1969)
Chloride Content (mg/L)
Nov. 1965
Oct. 1966
March 1969
1
867
4,500
288
24
2
—
871
875
36
3
866
12
12
12
—
4
869
12,000
200
5
862
—
8,000
400
6
868
18,000
8,875
407
—
7
868
26,250
662
—
8
865
1,000
490
—
9
870
14
16
10
868
25,500
9,850
917
11
868
31,000
7,500
550
—
12
864
8,750
740
13
865
—
6,875
1,355
—
14
864
3,125
292
—
15
864
302
1,725
16
864
22,750
15,500
1,230
17
—
868
10,000
1,300
18
864
5,600
1,500
600
19
869
27
25
300
20
862
15,000
1,400
21
865
9,000
1,100
22
862
4,800
4,800
117
23
859
5,250
6,625
779
24
861
33
235
27
—
25
860
95
40
880
W
-1
20
320
