Groundwater Use is Affecting Little Rock Creek
There are indications that groundwater use is affecting stream flows in Little Rock Creek, an important coldwater trout stream in Central Minnesota. The DNR established the Little Rock Creek Area because we are concerned that total permitted groundwater use in the area might not be sustainable. Groundwater use might have a negative impact on Little Rock Creek.
Groundwater use is vital to the people and economy in the Little Rock Creek Area. The DNR wants individuals, communities and businesses to keep using groundwater. However, the DNR can issue permits for groundwater use only if the use is sustainable as defined by statute.
Since January 2016, the DNR has met with residents, permitted water users, and local government leaders in the Little Rock Creek Area to discuss, analyze, and plan for the sustainable and continued use of groundwater in the area. Through those discussions, the DNR developed an action plan. The plan includes a variety of actions the DNR will take through 2022, designed to ensure a sustainable groundwater supply while protecting Little Rock Creek.
The DNR will collect and analyze additional information to determine whether groundwater use is, or is not having a negative impact on Little Rock Creek.
Keeping the Public Informed
The DNR will continue to work with individuals, communities and businesses. Residents and businesses will be informed about groundwater management actions through the DNR website, email and at least one public meeting per year.
Little Rock Creek Area stakeholder meetings will be announced mainly through email. Scroll to the bottom of this page and enter your email address next to “Sign up for updates”.
The DNR will take the following actions to support sustainable use of groundwater in the Little Rock Creek Area.
- Protected Flow and Sustainable Diversion Limit
According to Minnesota Rules, a stream's "protected flow" is the amount of water required in the watercourse to meet the needs of fish and wildlife habitat, water quality and priority downstream users. Once a protected flow is established for a stream, the DNR can calculate the amount of groundwater use that is sustainable.
In order to inform future decisions about a protected flow and a sustainable diversion limit for Little Rock Creek, the DNR will do the following data collection and analysis before 2019:
- Expand collection of stream flow and temperature data on Little Rock Creek.
- Continue monitoring groundwater levels throughout the Little Rock Creek Area.
- Measure and analyze fish habitats in Little Rock Creek.
- Finalize a groundwater flow analysis.
- Cumulative Use and Negative Impact
In relation to water appropriations, negative impact is a change in hydrology sufficient to cause ecosystem harm or alter riparian uses long-term. In order to determine if cumulative use is having a negative impact on Little Rock Creek, the DNR will work with the public to:
- Establish a protected flow for Little Rock Creek.
- Establish a sustainable diversion limit for cumulative groundwater appropriations in the Little Rock Creek Area.
- Determine whether cumulative use is greater than the sustainable diversion limit.
- Hydrology and Biology
Important natural resources in the Little Rock Creek Area include wetland complexes, native prairie remnants and two cold water streams. There are also forested areas, warm water streams and the northern edge of Little Rock Lake.
In order to improve the hydrology and biology of Little Rock Creek, the DNR will evaluate the impact and feasibility of a variety of management actions. Then, the DNR will work with stakeholders to determine the most appropriate management actions to keep permitted water use within the sustainable diversion limit. The management actions to be evaluated include:
- Managing water levels differently in the Sartell Wildlife Management Area.
- Pumping groundwater into Little Rock Creek and/or Bunker Hill Creek during times of low stream flow (stream augmentation).
- Enhanced water conservation by current water appropriation permit holders.
- Additional groundwater recharge.
- A new rural water distribution system to supply irrigation water from wells that are farther away from the creek.
- Installing vegetated riparian buffers to improve temperature, sediment, and other water quality aspects of the creek.
- Modifying existing water appropriation permits (evaluate the impact not only on water quality and fish habitat but also on the regional economy).
- Water Use
In order to more accurately estimate the amount of water used in the Little Rock Creek Area, the DNR will do the following over the next several years:
- Work with all water appropriation permit holders to evaluate the accuracy of their reported water use estimates. This will start with a group of irrigators who volunteered to compare their own existing water use estimates to flow meter measurements.
- Clarify the number of livestock operations in the Little Rock Creek area and their annual groundwater use.
- Clarify the extend of non-permitted groundwater uses in the area, including low-volume domestic wells and any high-volume users operating without permits.
- Permitted Water Use
In order to support the continued permitting of water use in the Little Rock Creek Area, the DNR will do the following:
- Issue only time-limited water use permits for new permits on permit amendments in the Little Rock Creek Area to assure compliance with Minnesota rule and statue. "Limited" means that permits are in force through December 2022.
- Extend all existing limited water use permits through December 2022 to allow for continued water use while data gathering and analysis are completed.
- Approve water use permit transfer if there are no changes in volume and all other legal requirements are met.
2021 Project Updates
Water Analysis Complete
In the spring of 2021, the DNR has completed its scientific analysis of water levels, groundwater flow, fish habitats and water temperature for Little Rock Creek. This work was guided by the “Sustainable Use of Groundwater in the Little Rock Creek Area: A DNR Action Plan” and will provide a foundation for discussions about sustainable use of groundwater in the Little Rock Creek Area. DNR invites the public to learn more about the analysis (linked below) and to ask questions of DNR staff that conducted the research.
- Assessment of instream temperatures in Little Rock Creek near Sartell WMA
- Irrigation system flow meter study
- Instream Flow Incremental Methodology (IFIM) Study for Little Rock Creek, Mississippi River –Sartell Watershed, Minnesota
- Groundwater Flow and Groundwater / Stream Interaction in the Little Rock Creek Area - Appendices, Figures
All of this work has been guided by the “Sustainable Use of Groundwater in the Little Rock Creek Area: A DNR Action Plan.” The plan’s aim is to assure that use of groundwater remains sustainable and consistent with state laws. Groundwater use is sustainable as defined by Minnesota Statutes when area groundwater is able to supply the needs of future generations and the proposed use will not harm ecosystems, degrade water, or reduce water levels beyond the reach of public water supply and private domestic wells.
Summary of Sustainability Analysis for Little Rock Creek
The groundwater flow analysis completed in March 2021 by the DNR shows that groundwater use in the Little Rock Creek area is reducing some of the seasonal low flows by more than 20% in four of twelve years analyzed. The associated fish habitat analysis showed that this amount of change in streamflow results in a loss of fish habitat during those periods.
Based on our analysis of fish habitats and species in Little Rock Creek, it appears that a sustainable diversion limit of 15% of the August median baseflow would avoid adverse impacts and meet the requirements for sustainable use in Minnesota Statutes.
The DNR’s temperature analysis also shows that the impoundment in the Sartell Wildlife Management Area contributes to raising water temperatures in Little Rock Creek below the impoundment dam. DNR wildlife managers are currently exploring options to adjust their management to improve conditions in the stream, while also preserving the benefits the impoundment provides for waterfowl and waterfowl hunting.
In addition to the June public meeting, the DNR will continue consulting with stakeholders, consisting of individual conversations, availability for questions, meetings and exploration of options, starting with the ideas laid out in the Sustainable Use of Groundwater in the Little Rock Creek Area: A DNR Action Plan. Most importantly, we will all need to continue listening to each other – agency staff and stakeholders alike – and build on the partnership we have begun.
Working together, we can (and will) plot a course that allows us to continue reaping its economic and ecological benefits, securing them not only for us today, but also for future Minnesotans.
2020 Project Updates
- Mark Hauck, Little Rock Creek Area Project Manager, 320-223-7846