WSP08349

• File Number: 8407
• Description: Platte River Basin - River Basin General Publications
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 12/6/1995
• Author: USGS
• Title: Quantity and Quality of Ground-Water Discharge to the South Platte River - Denver to Ft Lupton - Colorado - August 1992 through July 1993
• Water Supply Pro - Doc Type: Report/Study

1321f)-'l ~'7

Tsble 3. Construction details for monitoring wells at the McKay Road, Henderson, and Road 8 sites

Depth below Depth below
Total depth below land surface land surface location
Well land surface to top of to bottom of relative to
(feet) screened interval screened Interval river channel
(feet) (feet)
McKay Road IA 14.5 9 14 Right bank.
McKay Road I B 30 24 29 Right bank.
McKay Road 2A 10.5 5 10 Left bank.
McKay Road 2B 29 23 28 Left bank.
Henderson lA 27.8 17.2 27.2 Right bank.
H~nderson IB 34 29 31 Right bank.
Henderson 2A II 5 10 Left bank.
H~ndersnn 2B 30 20 25 Left bank.
Road 8 lA 13 7.5 12.5 Right bank.
Road 8 1B 32 25.5 30.5 Right bank.
Road 8 2A 13.5 8 13 Left bank.
Road 8 2B 34 28 33 Left bank.

eters. Water samples from each of the piezometers
were composited using a weighting factor for the
discharge velocity of ground water measured at the
piezometers so that more water was added to the
composite from piezometers that had high discharge
velocities than from piezometers that had low dis-
charge velocities. No water was added to the compos-
ite from piezometers where the direction of ground-
water movement was from the river to the sediment.
The procedure described in this paragraph produced a
single, discharge-velocity-weighted water sample for
each cross section. Once the composite sample was
obtained, it was filtered, and samples were prepared
and preserved using the techniques described previ-
ously in this section for nutrient samples. The values
of specific conductance, pH, T, and DO reported
for each cross section were discharge-velocity-
weighted values using measurements made at the
five piezometers.
Temporary nested piezometers also were
installed at depths 00 to 12,30 to 48, and 80 to 84 in.
below the sediment/water interface in the river channel
to measure the variability in ground-water quality with
depth at the McKay Road, Henderson, and Road 8
monitoring-well sites (pI. I). Samples were collected
from August 1992 through January 1993 and in May
and July 1993. Samples were analyzed for specific
conductance, pH, T, DO, alkalinity, major ions, nutri-
ents, iron, and manganese. The three piezometers were
located within 6 in. of each other, and they were con-
structed of the same materials as those used at the
30 cross-section sites, except for the piezometer used to
collect the 80- to 84-in-deep sample, which was made
ofO.5-in inside-diameter aluminum-alloy conduit. The
vertical-profile samples were collect~d about I ft into
the river channel near the left bank at each site. Excep-

Ground-water samples were collected from the
monitoring wells using a submersible pump. Prior to
sample collection, the well was purged of three casing
volumes of water. After three casing volumes ofwater
were removed from the well, pumped water was routed
through an enclosed chamber in which specific conduc-
tance, pH, T, and DO electrodes were placed. Water
was passed through this chamber, and field properties
were measured U1Ttil they stabilized (typically IS to
20 minutes). After stabilization was reached, the
pump-discharge line was attached to a filtration device,
and water samples were filtered, preserved, and chilled
using the same procedure as described previously in
this section. Alkalinity titratiol1~ were perfonned on
filtered samples. Samples were analyzed by the
MWRD laboratory.

Ground-water samples were collected from
the 30 cross-section sites using a peristaltic pump
and the five piezometers installed I ft below the
sedimentlwater interface. Piezometer installation
at the cross-section sites was described in the
"Discharge Measurements" section. Measurements
were made from August 1992 through January 1993.
Samples were analyzed for specific conductance, pH,
T, DO, and nutrients. Field properties were measured
at each piezometer by pumping water from the piezom-
eter to the bottom of a plastic beaker in which specific
conductance, pH, T, and DO electrodes were placed.
Water was allowed to bottom fill the beaker and
overflow as measurements were taken. This process
continued U1Ttil the field properties stabilized (10 to
15 minutes). After field properties had stabilized, a
I-L sample of water was collected in a plastic bottle.
This procedure was repeated at each of the five piezom-

METHODS OF DATA COLLECTION 9