State engineers and DEQ brief lawmakers on Devil’s Lake outlets, sulfate constraints and sovereign‑lands implications
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Summary
State Water Resources staff outlined outlet capacities (combined 600 CFS), operational restrictions tied to downstream channel capacity and sulfate thresholds, and described pumping history and costs; DEQ said sulfate limits forced early shutdown of 2025 discharges and is working on real‑time monitoring to extend future seasons.
The state engineer and the Department of Environmental Quality told the Agriculture and Water Management Committee that removing water from Devil’s Lake remains a high priority but is constrained by downstream channel capacity, sulfate water‑quality limits and infrastructure limits on how low pumps can draw the lake.
State Engineer John Paskowski reviewed historic lake levels, explained the West End outlet (expanded to 250 cubic feet per second) and the East End outlet (350 CFS), and summarized the Tonakuli control structure’s purpose as a measured, non‑catastrophic outlet at the natural divide. He said the outlets and related flood protection work have moved roughly 1.6 million acre‑feet out of the basin since operations began, that outlet construction and related flood protections total roughly $100 million (not adjusted for inflation), and pumping costs to date are about $53 million.
Paskowski described two operational constraints: channel capacity north of Cooperstown — about 800 CFS before adjacent flood risk increases — and sulfate water‑quality endpoints that DEQ monitors at Lake Ashtabula (downstream compliance point set at 450 mg/L) and at Cooperstown (750 mg/L). Marty Harrelson of the DEQ said the agency curtailed discharges in 2025 after laboratory results showed Lake Ashtabula concentrations rising late in the season; he told the panel DEQ is pursuing more real‑time USGS monitoring and adaptive management steps so operators can throttle pumps rather than abruptly shut them off.
Committee members pressed for detail on when pumps last ran (August 2025 for the most recent operation), whether natural erosion could have relieved the divide earlier, and how sovereign lands are defined as water covers previously dry beds. Jen Verliger, general counsel for DWR, explained that land under current water surface elevation is treated as state sovereign land while the ordinary high‑water mark can shift as water levels change; she cautioned that courts look to historic navigability at statehood in some contexts.
Why it matters: pumping and outlets affect local landowners upstream and downstream, cross‑border water quality concerns, and long‑term costs. The committee sought more documentation on cumulative costs, the geographic stretch of the Cooperstown constraint, and the engineering and legal tradeoffs tied to potential future outlet operation.
Next steps: agencies said they would provide additional data on outlet run history, constraint lengths, pumped volumes and cost breakdowns for committee review.
