Farm Progress

4 tips relating to big rains

Ag Water Stewardship: How to roll with the ‘new normal’ of heavy rains.

Warren Formo

July 24, 2018

2 Min Read
NEW NORM: For four out of the last five years, parts of Minnesota experienced rains severe enough to trigger disaster declarations. Consider what you will do to address the negative challenges associated with flooding and runoff.

Heavy rains leading to disaster declarations have hit portions of Minnesota in four of the last five years, resulting in millions of dollars in damage to crops, homes and businesses, roads and other infrastructure, and presenting significant water quality challenges.

Some attribute the increased frequency of large rains to climate change; others simply call it a wet phase of usual climate cycles. I’ll set aside that debate for now to address the question of what can be done to reduce the negative impacts of the 100-year rains we seem to get every year.

1. Recognize that big rains are the main driver of agricultural runoff. Studies show that most nutrient and sediment losses occur under the highest flow conditions. A 2016 report on the Greater Blue Earth Basin in south-central Minnesota found that sediment loading increased dramatically with higher river levels.
An Illinois study found that discharges above the 90th percentile were responsible for more than 50% of nitrate export and 80% of phosphorus export. Monitoring data collected in Minnesota tell a similar story.

2. Second, incorporate this “new normal” into planning. As the old Creedence Clearwater Revival song wonders, “Who’ll stop the rain?” The answer is, no one.
However, perhaps we can manage it better once it’s on the ground. On ag lands, watch for evidence of erosion. Not all erosion can be stopped — yet perhaps you see differences in your area that can inform better tillage or placement of waterways. Systems that worked well in drier years may no longer be adequate. Timing of nutrient applications may need to change, both to help improve crop budgets and protect water resources.

3. Third, know that farmers are not alone. City planners and civil engineers are scrambling to address big rains also, and often with fewer available tools and incredible costs when systems fail.

4. Fourth, help regulatory agencies address the resulting variability in water data. Our current water quality standards do not adequately account for the variability that occurs from one year to the next. This results in a high number of water quality impairments, despite efforts to reduce runoff.

 Only in Lake Woebegone stories can everyone be “above average.” Perhaps water standards should be indexed to account for climate variability.

Formo is executive director of the Minnesota Agricultural Water Resource Center.

About the Author

Warren Formo

Warren Formo is executive director of the Minnesota Agricultural Water Resource Center.

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