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Discussion: Storm Water Management - Flood Prevention

posted on August 27, 2008 at 3:20 PM

Paul Yeager: The condition of the Great Lakes region and many of the state's watersheds has received much attention since the spring and summer flooding.

Before we talk about how best to do that let's define the problem the state faces:

·         Does Iowa face a climate change? 

·         Are too many wetlands and prairies being destroyed that have once helped filter and slow storm water? 

·         And what does the state need to do to encourage more communities and individuals to take action? 

To answer those questions are our guests this evening, Wayne Petersen is an urban conservationist with the Iowa Department of Agriculture and Land Stewardship and Mary Skopec is supervisor of watershed monitoring and assessment for the Iowa Department of Natural Resources.  To the two of you welcome to The Iowa Journal.  We first want to talk about climate change, though.  What evidence is there that points to climate change?  Let's start with you Mary.

Mary Skopec: There's a lot of evidence that the climate is changing and I think scientists have come to a universal agreement that the climate in Iowa and around the world is starting to change.

Paul Yeager: Are you in agreement with that statement, first?  And if you are, what is that impacting on what you're doing on a day-to-day basis?

Wayne Petersen: Well, of course, the modeling predicts more erratic, more intense weather patterns so I think we need to be monitoring how change occurs and adjust accordingly.  And I think probably the most prudent thing is to be prepared for change and ere on the side of caution.  In other words, don't keep doing what we've always been doing.

Paul Yeager: We need to change our ways, change our habits is what you're saying.  You were strong in the hand of consulting with what's going on in Okoboji.  What has happened there?  How can that be applied to a statewide level?  And if it would have been applied to a statewide level would we have lessened the impact of the flooding of 2008?

Wayne Petersen: Well, I can't say that we would have eliminated flooding by any means because with the new storm water management paradigm the goal of infiltrating water, rainfall, generating less runoff has targeted the historic rainfall patterns which have predominantly been frequent, small rains.  Historically 90% of rainfall has occurred as about a one, maybe one and a half inch rain or less.  Now, if we took that one inch or one and a half inch of runoff generated out of the loop, yes, you reduce peaks but not significantly when it comes to the type of weather we saw this year.  In the future we may see design standards upped, if you will, so that these practices like Mike May's can absorb a five year or ten year, hundred year storm and these are the four or five, seven inch type rains.  We can do that but we haven't asked people to do that yet.

Paul Yeager: So, when we're building projects like this or looking at change like this we cannot look at the old data of one to two inches, we have to look at the five, seven, ten, eleven inch.  Why is that?

Mary Skopec: Absolutely.  There's a term called stationarity is dead and essentially the past does not represent the future any more.  But in the climate change world we can expect to use 1900s data to predict what's going to happen in 2010 or beyond.  And I think what Wayne is getting to is that we have to look at a different paradigm of water management, we may have a lot of rain in June, July and then no rain in August and that is a problem for our water management not only for flooding but for droughts as well.  So, we can't just think about flooding, we have to think about the whole water system.

Paul Yeager: So, if we don't get as much rain say in 2009 we're going to have some water left around, we can't just let it all go downstream.  Is that what you're saying?

Mary Skopec: Absolutely and even this year the farmers were talking about the fact that when the flooding stopped the rain stopped and they were worried about maybe not having enough rain for their crops at the end of this year.  And so we're having these erratic patterns instead of consistent small rains throughout the year we're seeing big, big rains and then essentially the spigot gets turned off.  And the changes agricultural systems, it changes how we manage water for drinking water and a lot of different things.  That's different for us.

Paul Yeager: When you're not using history to back up some of your discussion points when you're talking to groups, I know you had said you had spent a lot of time up in the northwest part of the state talking about this plan, how do you not sound like somebody who is jumping up and down on a table saying the world is going to end to make your point valid?

Wayne Petersen: Well, of course, what we were trying to usher in with this new storm water paradigm was adding water quality protection to the traditional flood control objectives.  Traditionally with storm water management we have targeted big storms with flood control as the objective.  So, when we infiltrate runoff from the frequent small storms or infiltrate that first flush when we do get the big rain it's all about water quality enhancement and not flood control.  But maybe we will need to start combining the two through infiltration based practices.

Paul Yeager: Because business is just as important as nature to the Okoboji region because the Great Lakes region brings an incredible amount of tax revenue to this state and if the water quality goes away, say maybe what's happened in Clear Lake they're having to do some dredging this year -- that is a point I want to talk about is Clear Lake.  Can they learn from what's going on in Okoboji?  You're shaking your head first so I'll let you answer.

Mary Skopec: Yeah, actually I was going to make the point that Okoboji is an obvious revenue source for that part of the state but water quality and water is key to the rest of the state as well.  It may not be obvious because you don't have a crystal clear blue lake but water is key to our economic development throughout the state and Clear Lake can benefit from the storm water infiltration practices that Okoboji, Iowa City, Des Moines, all the communities can really benefit from that.  It may not be a lake that you're protecting but a drinking water source or a recreational source, paddling or canoeing.  So, it doesn't just end with an obvious beautiful resource.

Paul Yeager: We talk a little bit about Clear Lake and I've spent some time up there and know that there's been a big discussion and you've talked about this Wayne about the ag and urban discussion.  There's a lot of claim that ag is what has ruined Clear Lake or at least made it to where they have had to dredge it out.  So, let's talk about some of the -- is this taking out some of the blame where somebody is pointing a finger at another group or is this a working together saying this is what you're doing, this is what you're doing, we need to stop?

Wayne Petersen: Well, the question I have been asking since the flooding this year is if you lived in one of those watersheds that experienced record flooding did rain fall on your property?  If so, did runoff leave your property?  If so, did you contribute to the peak floods?  And if you have to answer yes to those questions then the next question is, what can you do and what will you do to reduce the volume of runoff that you generate?  And I think we need to ask that of the residential homeowner, the farmer, the large shopping center with large expanses of impervious parking lots, for instance, so it's everybody's problem and everybody needs to be part of the solution.  But one of my really I guess goals is if we can show an urban landowner or a business owner how much rain falls on your property over the course of a year, here is the challenge that you face to manage it sustainably I would like to think that that would grow an appreciation among the urban sector of the challenge a farmer has managing rainfall on hundreds or even thousands of acres so that we can build an urban-rural coalition for water quality protection.

Mary Skopec: And I think also the urban folks are more disconnected from their water resources.  You don't see that stream that's running through your particular town, it's in curbs and gutters and it's underground.  The farmer has a much more connected view to the streams because they are out on that landscape.  But I agree, this is really both urban and rural and we can't separate that.

Paul Yeager: The rural area we plant fence row to fence row, we're encouraged to have more production, there's been a lot more tiling of land, it's hard to find an acre that's not tiled.  What has tiling done, Wayne I'll start with you, to contribute or alleviate this flood management or water management problem?

Wayne Petersen: I've been fielding that question and talking to a number of people.  It may be counterintuitive but in my opinion it's the volume of runoff that caused our problems and not flow coming out of a tile line.  Theoretically tiling can actually give the landscape a little more potential to infiltrate.  A saturated landscape can't take on any more water.  Tile pulls extra water that is in the pore space in the soil profile out of there.  But if you're up in the Loeb country, some of the intakes in the potholes will get rid of water a little faster off of that pothole country.  And I heard farmers talk about how we had enough rain this year that water cascaded from pothole to pothole to pothole.  That's what causes flooding.

Paul Yeager: Mary, same question.

Mary Skopec: I take a different view than what Wayne says.  I think there is something to be said for the tiling bringing down the water table.  I think the issue this year is whether or not we even had saturated soils.  And that question really hasn't been answered and we really don't have enough data yet to say that.  But I think one thing that tiling does is it connects the entire landscape to that stream in a much more rapid timeframe than we ever saw before.  So, I think we need to slow that water down either through in the tiles keeping that water in the landscape or having, again, better infiltration on the farmland.  One thing we haven't talked at all about is that water is held in the landscape through a variety of things including vegetation or organic matter.  And we know there are a lot of our soils this year really were bare Earth because of the timing, we had a late winter, you had late planting and maybe the combination of not having a lot of vegetation on the landscape, having that tile connecting all that land back to the stream really, again, exacerbated our problems.

Paul Yeager: A perfect storm of sorts?

Mary Skopec: A perfect storm of sorts, exactly.

Wayne Petersen: And I totally agree with Mary that a key component is soil quality and it is my opinion that over the century or more of intensive tillage based agriculture we have experienced soil quality degradation which means we have less organic matter content, we have soil structure that is not as good as it once was which does not allow that landscape to absorb as much.

Mary Skopec: Exactly, I think that the actual amount that that landscape can hold is less than it used to be and we don't really give farmers incentives to increase organic matter.  That is not a goal generally in our agricultural practices.

Paul Yeager: If they're not paid to do it they might not do it.  If the farmer is paid to do it and in the latest farm bill there was some conservation but probably not enough, it's not going to require enough and we could use more wetlands, that would be one area that farmers could improve upon?

Mary Skopec: I think wetlands would help, I think wetlands do hold back some of that water and, again, we want to keep the water on the landscape not only for flooding but for water quality because we know that water on the landscape doesn't cause problems in the stream for drinking water or recreational problems.  But, again, I think it's a matter of having a healthy watershed and having prairies and wetlands and good soil quality both in the urban and the rural areas to have a better water system.

Wayne Petersen: And one of the other problems with the delayed planting this year, the cool, wet spring, crops got in late we did not have that perennial vegetation throughout the watersheds like we once did that is pumping water out of that landscape.  So, it's a combination of things.

Paul Yeager: We're just about under a minute here so I have to ask you what is the next Okoboji project across the state?

Wayne Petersen: Well, we're trying to replicate that all over and it's picking up steam.  Okoboji was our breakthrough but many, many more communities are jumping on.

Paul Yeager: So, we're seeing that's the direction, it's not going to be just a singular thing, that it's going to spread?

Wayne Petersen: I hope it's a genie that is not going back in that bottle.

Mary Skopec: It's going to spread.

Paul Yeager: It's going to spread.  Is it going to take more policy change to get us there?

Mary Skopec: I think it takes policy change, I think it takes vision because people are used to doing the same things, curbs and gutters are the way that people do urban landscapes and that's not going to work for storm water.  So, it's a matter of having some vision for your community.

Paul Yeager: And that's what you have to do and there's developers that are trying to do this as well from my understanding in some of their development ways that they are going.

Wayne Petersen: Going green will sell.

Paul Yeager: Going green will sell, it is selling in developments across the state.

Mary Skopec: It is, absolutely, I think people really like seeing green communities and having pavers instead of concrete.


Tags: climate change economy Energy/Environment floods HEAT Iowa lakes rivers tourism water water quality wetlands


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