Laserfiche WebLink
Ryegrass UL and Ryegrass galefill Landfill Upgradient Groundwater <br />Investigation <br />Kat itas Comy Solid Waite <br />Three cemented bollards will be placed around the well for protection. The above -ground monument <br />will be lockable. <br />4.3 Well Development & Testing <br />4.3.1 Well Development <br />The well will be developed by the driller following construction using surge and bail/pump <br />techniques. Development will proceed until clear formation water free from turbidity is observed. <br />Development will attempt to obtain less than 5 Nephelometric Turbidity Units (NTU). If 5 NTU cannot <br />be obtained, development wilt occur until the turbidity is stabilized. <br />4.3.2 Pump Placement <br />Following completion of development, the licensed well driller will deploythe dedicated pump, a <br />Redi-Flo 2 electric submersible pump, into the well. The pump will likely be placed a minimum of two- <br />thirds of the depth of the screen to allow sufficient drawdown during sampling. Several of the <br />existing monitoring wells go dry during purging at low flow rates indicating that pump placement <br />within the middle of the screen is not suitable for the aq uifer conditions. If development observations <br />suggest the well is likely to go dry, the pump will likely be placed near the total bottom of the screen. <br />4.3. 3 Short -rearm pumping 'Pest <br />Approximately 1 week after well development, a short-term pumping test of the well will be <br />conducted. The test will be comprised of a 1-hour pumping test using the dedicated pump with <br />measurement of drawdown and recovery using a water level sounder with measurements to the <br />nearest 0.01 foot. Pumping rates will be monitored with a graduated cylinder and documented <br />throughout the test. The drawdown and recovery data will be analyzed by a licensed hydrogeologist <br />to estimate aquifer transmissivity near the well. <br />4.3.4 Well Survey <br />Each of the monitoring wells (new and existing) will be surveyed under the supervision of a <br />Washington State licensed professional land surveyor. The survey will be conducted in Ecology <br />geospatial data standards North American Vertical Datum of 1988 (NAVD88) and North American <br />Datum of 1983 (NAD83) as follows: <br />r Measurements will betaken at the north side of the top of the permanent well casing and <br />ground elevation. <br />m Vertical accuracy will be 0.01 foot or less. <br />■ Horizontal accuracy will be 0.1 foot of less. <br />■ The survey will include measurements of at least two nearby benchmarks and repeat <br />measurements through cross triangulation to demonstrate precision, accuracy, and <br />consistency. <br />April 2024 1553-4-763-010 <br />Revised May 2024 <br />