RAPID CITY, S.D. – Lack of inflows into Pactola Reservoir has triggered a prolonged water restriction schedule for Rapid City.

On Wednesday, city officials said the storage condition status for Pactola Reservoir was being elevated from ‘concern status’ to ‘alert status’ which would result in expanding water conservation measures – watering restrictions – throughout the year.

City Water Superintendent Eric Boyda said the mean monthly inflows this summer have been dramatically lower than average. The August mean monthly inflow is 50.05 cubic feet per second (cfs). Despite the recent rain events, the inflows were gauged at 20.6 cfs on Monday, August 17. Previous to the recent rain event, flows had been as low as 12.2cfs in August. July’s total inflows were 30 percent of the mean.

“So even though we got some record-breaking precipitation here in Rapid City, those storms didn’t occur in the upper watershed,” Boyda said. “Our intent is to not change the conservation levels until there’s a substantial change in the inflow.”

Pactola Reservoir was constructed in the 1950s to store water for downstream needs.

“Pactola is at 73 percent full, and the facility is functioning just as it was designed,” Ron Bengs, Bureau of Reclamation, said. “It was designed to hold water and buffer these dry years and that’s just what it’s doing.”

Since the Bureau has kept records in 1956, prolonged droughts have lowered the level of Pactola below what it is today.

Bengs said in 1962 the reservoir was 84 feet lower than it is today; in 1991 and 2008 the reservoir was about 28 feet lower than what it is today.

Pactola serves several downstream users with irrigation and city needs. Bengs said his office works closely with the City of Rapid City to manage those needs and the amount of water released from Pactola.

“We don’t send more water down Rapid Creek than we absolutely need to, to meet those obligations we have and keep as much as we can in the reservoir,” Bengs said.

Boyda said Pactola was at over 73 percent of its storage level and Deerfield Lake was at 92 percent.

“So, we still have multiple years of surface water storage in both of these reservoirs,” Boyda said. “And remember that the whole point of the reservoirs is to have multiple years of storage so that we can weather droughts like we’re going through right now.”

Earlier this spring, City officials elevated the storage condition status from ‘normal status’ to ‘concern status’ due to the water levels at Pactola and the lack of inflows due to no snowpack in the watersheds above the reservoir. Water conservation measures are implemented each year on June 1, but were implemented in late March this year due to the reservoir levels and lack of inflows.

The current ‘alert status’ designation means water restrictions will continue beyond the end of September. City water customers will continue with the same daily watering schedule in place since late March.  

No watering is allowed between the hours of 9 a.m. and 6 p.m. daily.  Odd-numbered addresses are allowed to water on odd-numbered calendar days.  Even-numbered addresses are allowed to water on even-numbered calendar days. No outside watering is allowed on the 31st day of any month. Waivers can be granted for certain seeding and sodding needs.

Water conservation tips for homeowners include planting low-water native plants, irrigating in the early morning, allowing grass to grow longer and leave clippings on the lawn, maintain sprinkler systems, and irrigate longer but less frequently.

Conserving water goes beyond watering restrictions for city residents. Boyda said the City has taken several steps to conserve water – creating low-water native-plant landscapes that don’t require irrigation, utilizing equipment to identify leaks, and providing public education to encourage water conservation.

Below is an explanation for the four storage status condition levels for Pactola Reservoir:

•  Normal Status. The aforesaid measures shall apply during the months of June, July and August of each year.

•  Concern Status. During such time as Pactola Reservoir contains less than 48,950 acre feet of water or the inflow to Pactola Reservoir is less than 90% of the mean monthly average, the aforesaid measures shall apply from April 1 through September 30.

•  Alert Status. During such time as Pactola Reservoir contains less than 26,950 acre feet of water or the inflows to Pactola Reservoir are less than 50% of the mean monthly average, the aforesaid measures shall apply throughout the entire year.

•  Critical Status. During such time as Pactola Reservoir contains less than 13,750 acre feet of water or the inflows to Pactola Reservoir are less than 25% of the mean monthly average no outside watering, regardless of hours or days, is permitted.