Subsections

• GroundwaterCharacterization Definitions
• Measuring Water Quality
• Measuring Water Level in a Well: Using a Beeper Tape
• Measuring Groundwater Discharge: Rising Head Slug Test
  • Withdrawal Slug Test Analysis

GroundwaterCharacterization Activities

GroundwaterCharacterization Parameters to be Measured

Static Water Level

using beeper tape

Water Chemistry

Temperature

by thermometer, pH meter or dissolved oxygen meter

pH

by pH meter

Turbidity

by portable turbidimeter

Nitrate

by spectrophotometer (colorimeter)

D.O.

by dissolved oxygen meter

Water Level Recovery

monitor return of water levels to static condition after water samples are removed. Use beeper tape.

GroundwaterCharacterization Field Procedure

1. measure static water level in borehole (all groups do this together before water sampling begins), use ``beeper tape''
2. collect water sample from borehole
   1. following bailer procedure collect 1 liter sample
   2. save one split in 500 ml amber glass bottle, cap the bottle leaving no air space (for D.O. and nitrate measurement)
   3. Caution: after 1/2 the contents of the bailer have been poured out, water will begin to leave the bottom end of the bailer as well as the top
3. Monitor water level recovery
   1. form a water level measuring group composed of one member of each of the regular groups for the day
   2. this group will record water levels, beginning immediately after the last group has extracted its sample from the borehole.
   3. follow the slug test procedure, using the beeper tape. Record data in suggested format (Fig. 6.6)
4. Measure chemical state. The following tasks may be performed in any order, if you find yourself waiting for a piece of equipment, try to start on one of the other tasks
   1. temperature (by thermometer or meter)
   2. pH (follow pH-meter procedure)
   3. dissolved oxygen content, electrical conductivity, salinity, see D.O. meter procedure
   4. Measure Turbidity, see turbidity procedure
   5. Prepare Filtered Split, see filtration procedure
5. Measure Nitrate Content, colorimetry procedure

GroundwaterCharacterization Comparative Results

See Tables 6.2-6.4 for sample data from earlier semesters, and Fig. 6.9 for slug test results.

Table 6.2: Class well sampling results, SE corner of Synergy Parkway and Rutford Dr., UTD campus, Oct. 10th 1998. The instructor and TA comprise ``Group W'', data gathered Oct. 7th. Static water depth was 10.5 ft.

		Group
Component	Units	A	B	C	W
Static depth to water	ft	10.1	10.1	10.1	10.5
Conductivity	$\mu$S	799	818	764	805
Salinity	ppt	0.40	0.4	0.2	0.4
pH		7.28	7.42	7.44	7.35
Turbidity	NTU	7.15	10.2	1.93	3.19
D.O.	% sat	21.2	7.1	11	5.5
D.O.	mg/l		0.6	1.0	0.5
Nitrate	ppm	1.9	1.8	1.2	0.6
Water Temp.	${\rm ^\circ C }$	20.9	20.8	21.9	21.6

Table 6.3: Class well sampling results, SE corner of Synergy Parkway and Rutford Dr., UTD campus, Sat. Feb. 16, 2000. Initial depth to water was 8.4 ft.

	Group
Parameter	GROUP A	GROUP B	GROUP C	GROUP D
	1st liter	2nd liter	3rd liter	4th liter
Temp (C)	20.7	21.7	21.1	20.0
pH	7.11	7.13	7.15	7.24
Turbidity (NTU)	1.2	1.4	2.0	3.3
DO (%)	26.5	24.6	24.4	29.1
DO (mg/L)	2.27	2.11	2.08	2.59
Conductivity (uS)	814	825	818	813
Salinity (ppt)	0.4	0.4	0.4	0.4
Total Disolved Solid (TDS)	350	360	340	330
Nitrates (mg/L)	0.80	0.8	0.9	1.0

Table 6.4: Class well sampling results, SE corner of Synergy Parkway and Rutford Dr., UTD campus, June 24, 2000. Initial depth to water was 6.1 ft.

	Group
Parameter	GROUP A	GROUP B
	1st liter	2nd liter
Temp (C)	25.1	24.3
pH	5.87	6.4
Turbidity (NTU)	1.8	1.9
DO (%)	11.4	16.8
DO (mg/L)	0.92	1.37
Conductivity (uS)	682	684
Salinity (ppt)	0.3	0.3
Nitrates (mg/L)	1.1	1.3

GroundwaterCharacterization Instructions for Discussion

Include the following topics in your discussion

• analyze the withdrawal slug test data (water level recovery vs. time) using the Hvorslev method described in p. 141-145, Sanders (1998)
• Discuss your own group's results, including any significant potential sources of error.
• Compare your results to those of the other groups, and (if desired) historical data, and try to explain any differences.
• Compare your results to the stream chemistry data we took earlier, and discuss any differences you see.
• Compare the specific discharge to the streamflow you measured in Lab 2. Does the stream receive a large or small percentage of what is flowing in the aquifer?

GroundwaterCharacterization Makeup Lab

Read the ``Lab 4 Activities'' section of the handouts. Since the UTD borehole was destroyed several months ago, we will use previous classes' data (see attached sheets). Break up into your groups to discuss the results, in preparation for writing your lab report on this data.

Figure 6.9: UTD Borehole slug test comparison, plotted as log fractional drawdown ($\frac{H}{H_o}$ vs. time). Depth to water table given in parenthesis.