Landowners have a right to pump groundwater on their property. However, many citizens who live close to the river have chosen to siphon water from the Colorado instead. Well owners can cure this in several ways, as relates the Arizona Republic:

 To comply with the new procedures, well owners can seek an individual water right,join an existing water district or become a customer of a city or provider with rights to Colorado River water. They could continue to pump waterfrom the well but only within the limits of the water right or provider.

Well owners who can't acquire water rights can't continue to use their wells.

The bureau is still trying to figure out how many wells have tapped the river or the exact amount of water pumped. Hydrologists estimate the annual losses at 9,000 to 15,000 acre-feet, enough water to serve Lake Havasu City for most of a year.

More than half the wells identified are in Arizona.

The federal crackdown comes at a time when the bureau and the seven Colorado Riverstates are trying to stretch water supplies to meet growing demand and avert drought-related shortages.

The states adopted a drought plan last year that outlines other efficiency measures, such as lining earthen canals to stop seepage and removing invasive plants that use too much water.

Bringing illegal wells into compliance would help ensure the river's long-term sustainability and protect users with a legal right to the resource, said Lorri Gray, director of the bureau's Lower Colorado Region.

"If someone is using Colorado River water without an entitlement, that harms the entitlement holders in Arizona, California and Nevada who do have one," Gray said.

Here in Arizona, we are contending with an additional problem in that the state laws don't acknowledge the physical connection between surface water and groundwater as clearly as federal laws do. As a result, well owners are drawing water away from the Verde, San Pedro and other rivers, fearing few consequences, despite draining Arizona’s aquifers and rivers. This, in turn, has not only damaged the river, as environmental groups have argued for years, but the excessive groundwater pumping by the U.S. Army has dried up stretches of the San Pedro.

More from the newspaper: The 1,400-mile Colorado River is allocated among hundreds of water users, including states, cities, towns, Indian tribes and irrigation districts. An individual cannot divert water from the river without a legal allocation.

The bureau is targeting wells that pump water from that part of the river extending beyond its visible channel. The subsurface flow infiltrates aquifers that spread out away from the river banks. A well drilled too close to the river can divert water flowing into the river or pull water away from it.

Hydrologistshave mapped the river's floodplain and determined how far its flow extends, which varies. Water pumped from there is considered river water.

Most of the unregulated wells along the Colorado were drilled for landowners to provide water for households and limited agricultural use.

Although state and federal officials were aware of most of the wells, the water pumped was not accounted for properly. The new rules are meant to resolve that problem.

Working with the bureau, the U.S. Geological Survey is compiling an inventory of wells along the lower Colorado. So far, the USGS has found almost 3,000 in the three states.

The wells are clustered around towns on the river, such as Bullhead City, Lake Havasu City, Parker and Yuma.

Gray said the bureau will try to work with the well owners to keep a water supply.

"A key goal of this rule is to help those well owners who are using Colorado River water without a legal entitlement become lawful users of that water," she said.

In Arizona, as much as 10,000 acre-feet of water sits unallocated on the river and could be used to bring the well owners within the law. An acre-foot is 325,851 gallons, enough to serve one or two average households for one year.

The news is not as good in California or Nevada, where almost no unclaimed water is available.

The costs to well owners to comply with the new rules would vary, the bureau found. The Mohave Valley Irrigation and Drainage District has enough water to add new users and would charge $1.35 per 1,000 gallons. Bullhead City could add well owners to its user base and would not charge if the well produced less than 20 gallons per minute.

Same as so many of our natural resources, times have changed and how we utilize them will have to change as well. This is only the beginning.