The Standard Flow System is the most popular foot valve used with 5/8″x1/2″ Waterra tubing.
The Waterra Surge Block is an excellent well development tool. It simply press fits over the body of the D-25 Standard Flow Foot Valve. The Waterra Pump has a substantial capacity for developing monitoring wells because of the cyclical action of the valve in the well screen area. This characteristic can be utilized to remove silt and sediment that has accumulated in the foot of the monitoring well and can also be used to remove fines from the sand pack and well screen.
The surge block effectively increases the outside diameter of D-25 Foot Valves to:
- 1.88 inch for 2 inch wells and
- 3.88 inch in 4 inch wells, reducing the annular gap between the valve and the inside of the well screen to approximately 1/16 inch. This results in a significant increase in the surging action of the Foot Valve – Surge Block combo.
Please note – Surge Blocks, Foot Valves and Tubing are SOLD SEPARATELY.
Surge and Pump
The use of the Waterra Pump and Waterra Surge Blocks- Standard Flow together is one of the most effective methods for developing monitoring wells because it simultaneously surges and pumps the well. This frees up silt and sediment in the sand pack and screen, and breaks down bridging, drawing these particles into the well and then removes this material from the well.
Recommended Method of Use
The recommended method for developing a monitoring well with the Waterra Pump and Surge Block is to begin the development process with the surge block near the top of the well screen. Operate the pump with the surge block in this position until the turbidity level of the water being delivered from the pump decreases to an acceptable level. Once this level is reached then the surge block is lowered in the well screen one to two feet and the process is repeated.
Developing wells in this manner is one of the best methods, often resulting in turbidity levels below 10 NTUs.
Waterra Surge Blocks – Standard Flow are used with D-25 Foot Valves for 2 and 4 inch monitoring wells.