Perry Subsurface Drip Irrigation Project
Service provided: Dispersal of natural gas produced water
Location: Sheridan County, Wyoming
Daily capacity: 15,000 barrels (2.5 ML) per day
Project start date: January 2005
Area developed: 210 ac (84 ha) , 430 miles (687 km) drip tubing, 9 miles (14 km) pipeline, 28 ac-ft (22.5 ML) pond capacity
Water quality: EC = 2200 µS/cm, SAR = 48, Na = 500, HCO3 = 1400 mg/L, TDS = 1390 mg/L
Crops produced: alfalfa (lucerne) and mixed cool season grasses
This was BeneTerra’s first full-scale project using subsurface drip irrigation to disperse associated water from coal seam gas production. It was built in three phases over two years to accommodate increased customer demand for water dispersal. At peak times it has handled as much as 24,000 barrels (4 ML) per day. As water volumes have decreased, current dispersal is 10,000 barrels per day. More than 33 million barrels (3970 ML) have been dispersed at this project site.
These SDI fields have produced impressive hay crops. The rancher has been able to increase his herd size and supply hay to two other ranches. After ten growing seasons the topsoil on this ranch is relatively sodium free. The subsoils exhibit a buildup of sodium that is offset by naturally occurring calcium minerals. Of the six groundwater monitoring wells on the project, two have exhibited a small increase in total dissolved solids, presumably from leaching of naturally occurring salts with the SDI water. The TDS levels have remained within legal limits.