BCCZO -- Well Water Levels -- GGU_Slug_Test -- Gordon Gulch Upper -- (2016)

OVERVIEW

Description/Abstract

A series of slug tests were performed at groundwater monitoring wells in upper Gordon Gulch. The spefic wells tested were GGU_GW1, GGU_GW2, GGU_GW3, GGU_GW4, GGU_GW5, and GGU_GW6. Slug tests were perfomed by Steven Henning, a master's candidate at CU Boulder. Tests were performed on 8/6-7/2015 and 9/12-13/015. The tests were perfomed to determine the hydraulic conductivity of the aquifer material around the monitoring wells.

Creator/Author

Steven Henning

CZOs

Boulder

Contact

Steven Henning (steven.henning@colorado.edu)

Subtitle

GGU_GW_1, GGU_GW_2, GGU_GW_6

SUBJECTS

Disciplines

Hydrology

Topics

Well Water Levels

Subtopic

GGU_Slug_Test

Keywords

None

Variables

None

Variables ODM2

Groundwater Depth

TEMPORAL

Date Start

2016-01-01

Date End

2016-01-02

SPATIAL

Field Areas

Gordon Gulch

Location

Gordon Gulch Upper

North latitude

40.020990999999995

South latitude

40.018815999999994

West longitude

-105.476828

East longitude

-105.476603

REFERENCE

CZO ID

6541

COMMENTS

Comments

Slug testes were performed fl]ollowing ASTM D4041 and ASTM D4044 standards. Materials used include 3 weighted slugs of various volumes, electric tape, an In-Situ Level Troll 700 pressure transducer, and An In-Situ RuggerReader field computer.

To initate a falling head slug test, depth to water in each well was first checked with an electric tape. Then the pressure transducer was lowered into the well to a depth below the estimated elevation of the bottom of the slug that was to be dropped. Then the depth to water was remeasured witht the electric tape and entered into the RuggedReader to calibrate the depth to water with the transducer. After calibrating the pressure transducer, active logging of the depth to water was started to get a steady baseline recorded. After approximately 30 seconds of background recording, the slug was rapidly lowered intothe well to create an instantaneous rise in water level and head within the well. Initial displacement was noted and the water level was allowed to begin recovering. After the change in head had be reduced to 10% of the inital change, the test and water level recoding was stopped. This process is repeated for a rising head test, with the exception of the slug being rapidly withdrawn from the well rather than being lowered into it. In some cases the testing of the well was stopped before the water level recoved to within 10% of its starting value to to time constraints or inclement weather.

The data gathered from the pressure transducers has not been edited, but at least 2 of the 26 tests performed (Well4, Falling Test 2; Well6, Rising Test 3) show instrument error that should be accounted for in some way before using the data.