Michigan: New Report Shows Big Increase in Extreme Storms

The kind of deluges that flooded Detroit this year and Grand Rapids last year are part of 50-year trend of increasingly frequent extreme storms in Michigan. That’s according to a new report we released today along with the Rocky Mountain Climate Organization (RMCO). Extreme Storms in Michigan also found a 128% increase in big storms in densely populated Southern Michigan.

The report is based on an analysis of daily precipitation records from 37 weather stations over 50 years. It is the most comprehensive analysis yet of daily precipitation trends in Michigan, and by including data through 2013 has the most recent data of any analysis of precipitation in the Midwest.

The report documents an 89 percent increase in the annual frequency of extreme precipitation events—defined as 2 inches or more in a day—across the state over the last 50 years.

The data are further broken out regionally, with storms having increased by 62% in the Upper Peninsula; 42% in northern portions of the Lower Peninsula; and a whopping 128% increase in southern Michigan, home to most of Michigan’s residents.

The report’s principle author, RMCO’s Stephen Saunders, notes:

“The report digs deep into the data to confirm something most Michiganders already guessed—dangerous, extreme storms are on the rise across the state. Global studies already show climate change driving more extreme precipitation, and now we’ve documented how great the increase has been in Michigan, where aging infrastructure makes the resulting floods even worse.”

The flooding is dangerous and it costs the state billions. Earlier this year, six inches of rain fell in Detroit in eight hours, causing over $1 Billion in damage. April 2013 storms of two inch-plus rain wreaked havoc across the state, blocking streets, flooding basements and damaging property. In Grand Rapids, the river crested 21 feet above flood stage. Both storms prompted federal disaster designation. 

Let’s be clear: this is a climate change issue, and a changing climate is one of the most serious threats Michigan has ever faced. The report details how flood risk will grow if we don’t cut the pollution that causes climate change.

That’s where the Administration’s historic Clean Power Plan comes in. The US Environmental Protection Agency has proposed a common sense format that lets each state decide how best to cut its carbon pollution. Michigan can support the Clean Power Plan by ramping up the use of renewables like solar and wind power, and using energy smarter by using it more efficiently.

NRDC is working to pass legislation to help Michigan get 30% of its power from renewables like solar and wind and energy efficiency.  That legislation would double investment in smart energy use and reform the way utilities are paid so that they can maintain a reliable grid. 

Governor Snyder has endorsed these concepts.

The Obama Administration has made it clear that dealing with climate change means more than just cutting the pollution that causes it. President Obama convened a Task Force of local, state and tribal leaders about a year ago — including Grand Rapids Mayor George Heartwell — which recently released a suite of recommendations and actions that includes template preparedness plans, centralized resources in the form of a ‘US Climate Resilience Toolkit’, and “disaster recovery app.” You can read my blog on the Task Force recommendations here. On Wednesday, the White House announced the first winners of its Climate Change Champions Competition, highlighting cities and communities on the cutting edge of preparing for climate impacts (the Sault Ste. Marie Tribe of Chippewa Indians in northwest Michigan was among them). Winning communities will be assigned a federal coordinator to help them maximize further their work and fully take advantage of all government preparedness programs and resources.

But getting back to the storms--when it rains hard and fast, water tends to overwhelm the systems designed to deal with it. That’s especially true in communities that have combined sewer and wastewater systems. Unfortunately, Michigan has a lot of these—46--the third highest amount in the nation.

These old systems weren’t designed to handle the kind of rains our report details. And when they overflow, it causes a serious public health risk because they dump untreated human sewage and industrial waste into water that in many cases we rely on for drinking supply.

The study includes a new analysis of combined sewer overflows (CSO’s), finding that 76 percent of the worst incidents resulted from storms of two inches or more per day.  Of the largest recent CSOs from each of 17 combined sewer systems in Michigan having overflows, 13 were associated with two inches or more of precipitation in a day.

No one wants raw human waste in their drinking water supply.

We’ve got to think differently about how we deal with all this water.

That means creating more green infrastructure systems that soak up the water before it can get to the sewers, using natural surfaces to collect, filter and hold rain where it falls. Green infrastructure systems are much cheaper and faster to build than big concrete and steel projects. Forward—looking cities around the country are planting more trees and shrubs, creating more green roofs, building more bioswales, and replacing old asphalt with porous pavement that lets rain pass through into the ground. They’re also creating more parks and revitalizing wetlands.

Severe storms also put private drinking water supplies at risk. That’s a big concern in Michigan as the study notes that more people in Michigan rely on private wells than in any other state -- over one million households.

A lot to think about, and a lot to act on.