Oregon water authorities have raised the regulatory standards for drilling irrigation wells despite objections from critics, who claim the new rules are overly restrictive.

Under the new rules, approved unanimously by the Oregon Water Resources Commission on Sept. 12, farmers and other water users can drill new wells only if they’re proven not to cause groundwater declines or stream flow reductions.

“The reason we are engaging in this rule-making is to limit any potential future over-allocation,” said Justin Iverson, groundwater section manager for the Oregon Water Resources Department, which is overseen by the commission.

The revised regulations are a departure from the OWRD’s historical approach, which often allowed new agricultural or municipal wells even if the impacts to groundwater were uncertain.

The changes were driven by steep aquifer declines in the Harney Basin and elsewhere, which OWRD admitted were caused by over-pumping permitted under its previous regulations.

Depleted groundwater can result in domestic wells drying up, the curtailment of existing water rights and problems with water quality, Iverson said.

“Statewide monitoring indicates parts of the state have groundwater levels that are declining as well as surface waters dependent on groundwater discharges that are over-allocated,” he said.

Critics say they recognize the need for more sustainable groundwater development but argue the agency has effectively declared a widespread moratorium on new wells for agriculture and municipal uses, which are also affected by the regulatory overhaul.

The revisions don’t apply to domestic wells, which are exempt from permitting requirements.

Most of the state’s available surface waters are fully appropriated for irrigation and other uses, so critics worry the new rules will prevent farmers from investing in irrigation infrastructure that would allow them to grow higher-value crops.

The revised regulations have also raised fears among cities, which worry the groundwater restrictions will hinder construction meant to relieve the state’s housing shortages.

However, environmental groups strongly support the OWRD’s decision, which they consider long overdue as groundwater depletion can adversely affect surface waters on which ecosystems depend.

Environmental advocates say the new regulations have finally fully implemented landmark groundwater legislation that Oregon lawmakers passed nearly seven decades ago, closing loopholes that permitted excessive pumping.

According to OWRD, existing regulatory tools — such as declaring “critical groundwater areas” where pumping can be halted — were inadequate because they sought to remediate groundwater depletion, rather than preventing such declines in the first place.

Though critics argued the agency should have adopted more targeted basin-specific rules instead of a statewide regulation, OWRD officials responded the uniform approach is ultimately more protective, equitable and cost-effective.

However, agency officials admitted that some criticisms were valid regarding the effects of the rules on existing groundwater rights, which is why the OWRD decided against changing certain regulatory definitions that raised such concerns.

“We’re no longer proposing revisions to those,” said Laura Hartt, OWRD policy analyst and rule-making coordinator.