Since the interim report of April 1966 (Appendix B), the deep test hole south of Grande Prairie has been extended from 845 to 1,300 feet in order to explore the groundwater possibilities to the base of the Wapiti Formation. The hole, which has been subsequently abandoned, is thought to be bottomed in Smoky River (Lea Park) shale first encountered at 1270 feet so that the full extent of the Wapiti has been tested at this location.
In deepening the hole only one aquifer of note (at 875 to 895 feet) was encountered. The test hole flowed at 17 igpm when this aquifer was first encountered but the flow declined to 5 igpm over a 19day period. The aquifer contained oil and gas as well as water and this, together with the low flow rates, made it obviously unsuitable as a source of sustained large supply of potable water. It was therefore not tested for yield.
A possible aquifer expected to be encountered at about 1,100 feet proved disappointing. A sandstone interval was encountered at 1,097 to 1,134 feet, but was fine grained and relatively impermeable due to argillaceous (kaolinitic?) cement.
In summary, three major bedrock aquifers were encountered during the drilling of this test hole. Of these, the first contained gas, and the other two oil and gas, as well as water. The first supply may be considered potable but is too low in yield to be considered for a large municipal supply; the other two are probably not potable because of the oil.
The three aquifers are:
1.Sandstone at 330 to 345 feet - water and gas - 20 year safe yield of less than 10 igpm.
2.Sandstone at 805 to 811 feet - water, gas and oil - 20 year safe yield of about 100 igpm.
3.Sandstone at 875 to S90 feet - water, gas and oil - not pump tested; rate of yield expected to be much lower than that for the second aquifer
Further details on the first two aquifers and on tests conducted on them are to be found in the interim report doted April 1966, enclosed. Also enclosed is a summary of progress, a log of the hole showing fluid potential measurements, a sketch showing completion and abandonment details, and a table of water analyses.
With the completion of this test hole, all groundwater possibilities in this locality, from ground level to the base of the Wapiti Formation, have been tested and have been found lacking for the needs of a city the size of Grande Prairie .