A river on trial: Assessing stream health in an agro-urban landscape
Streams and rivers provide many ecosystem services to humans, including water filtration, flood protection, and recreation among other benefits. In the agricultural Midwest, the impact of human land-use can degrade these freshwater ecosystems and limit their ability to deliver the same degree of services as streams flowing through watersheds with more natural land-use, such as prairies or forests. The Raccoon River is a socially and economically important river in Central Iowa. However, the high nitrate loads led the Des Moines Water Works to bring a lawsuit against upstream drainage districts over the river's water quality. My recent research has explored the variation in nitrate export and loss within the Raccoon River across space and through time. In addition, we have investigated the ecological value of land conservation as reflected by stream ecosystem function. Together, these studies seek to inform the management of river and streams in human-dominated landscapes.
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[00:00:00.580]Great, thanks Jess.
[00:00:02.460]And thank you all for being here, it's fantastic,
[00:00:05.880]that I was very excited when Jess offered me
[00:00:09.090]the invitation to come and speak in this series,
[00:00:11.530]and the opportunity to talk about
[00:00:14.010]how my research fits into a broader
[00:00:15.920]social and economic question that's really important here
[00:00:19.010]in the agricultural Midwest.
[00:00:20.750]So I know I'm on video
[00:00:23.060]so I'm gonna be very careful about
[00:00:24.970]how I talk about my science,
[00:00:27.133]because this is still preliminary work
[00:00:29.180]that I'm working on a publication right now
[00:00:32.060]that I'm gonna share the data with,
[00:00:33.530]and I'm gonna put it in the context of
[00:00:35.230]the recent Des Moines Water Works lawsuit
[00:00:37.870]that brought into question the role of agriculture
[00:00:40.344]and whether or not the Clean Water Act
[00:00:42.642]can address agricultural pollution.
[00:00:47.320]I like to start many of my talks
[00:00:50.180]by putting us in the frame of reference
[00:00:51.900]of how a biogeochemist might view the world,
[00:00:54.720]and I like to start with this image
[00:00:57.190]from one of the great 20th century conservationists,
[00:01:00.700]Ansel Adams, and this is a picture of
[00:01:02.780]the Grand Tetons and the Snake River below it,
[00:01:05.760]and in addition to this great conservationist,
[00:01:09.600]I like to think about, as a native Wisconsinite,
[00:01:13.080]I've read A Sand County Almanac a few times,
[00:01:15.800]though upon moving to Iowa I learned
[00:01:17.410]that Iowa tries to claim him as their own
[00:01:19.480]since he was born there.
[00:01:20.950]But his shack was in Wisconsin,
[00:01:23.460]and one of his essays is called Odyssey,
[00:01:25.970]which I find really fascinating as a biogeochemist again
[00:01:28.490]because he talks about two different atoms,
[00:01:30.180]atom X and atom Y.
[00:01:31.770]It's a short five-page essay in A Sand County Almanac,
[00:01:35.640]and this is just one passage near the end
[00:01:38.750]of atom X's travels.
[00:01:41.600]So he talks about atom X being pulled out of
[00:01:44.190]a limestone ledge and going through these
[00:01:46.580]many cycles through the biota and back into the soil,
[00:01:50.240]and he ends atom X's odyssey by saying,
[00:01:54.217]"An atom at large in the biota
[00:01:55.727]"is too free to know freedom;
[00:01:57.527]"an atom back in the sea has forgotten it.
[00:01:59.837]"For every atom lost to the sea,
[00:02:01.417]"the prairie pulls another out of the decaying rocks.
[00:02:04.267]"The only certain truth is that its creatures
[00:02:06.107]"must suck hard, live fast, and die often,
[00:02:08.647]"lest its losses exceed its gains."
[00:02:11.610]And that's a very poetic way to describe
[00:02:14.010]what a biogeochemist is interested in and studies.
[00:02:18.210]He then contrasts atom X's odyssey with atom Y's odyssey,
[00:02:24.870]and atom Y's odyssey is much shorter
[00:02:28.550]in this short, five-page essay,
[00:02:30.790]and atom Y's trip ends as you can see here,
[00:02:35.307]"On first reaching the pool, Y made several trips
[00:02:37.977]"through water plants, fish, and waterfowl.
[00:02:40.467]"But engineers build sewers as well as dams,
[00:02:42.937]"and down them comes the loot of
[00:02:44.827]"all the far hills and the sea.
[00:02:46.667]"The atoms that once grew pasque-flowers
[00:02:48.897]"to greet the returning plovers now lie inert,
[00:02:51.797]"confused, imprisoned in oily sludge."
[00:02:56.400]So we can see some of Aldo Leopold's
[00:02:59.430]more subjective thoughts in that odyssey,
[00:03:02.020]but as biogeochemists we're really interested
[00:03:04.620]in these natural processes on the molecular scale
[00:03:07.790]that define how matter and energy is transformed
[00:03:11.230]and transported across the landscape,
[00:03:13.010]and secondly how humans affect those processes.
[00:03:16.750]And the one molecule that I wanted to talk about today,
[00:03:20.190]is one of many that we can study
[00:03:22.880]but one that's very well-known here
[00:03:25.820]in the agricultural Midwest and that is nitrate.
[00:03:30.750]So I moved to Iowa just three years ago,
[00:03:33.400]and I'm a father of two children
[00:03:35.620]and so I feel like I can have a lot of puns in my talk.
[00:03:37.960]So I see Iowa as a real field of dreams for biogeochemists
[00:03:44.580]because if we were to compare some comparably sized
[00:03:47.170]capital cities around the Midwest,
[00:03:50.570]again I'm from Wisconsin so turning our eye
[00:03:53.350]towards Madison, searching the Wisconsin State Journal
[00:03:56.740]for the word nitrate turns up 59 hits,
[00:04:01.170]most of those were about sausage
[00:04:03.350]because it's Wisconsin and we eat a lot of hotdogs.
[00:04:07.730]Doing the same search here in Lincoln,
[00:04:09.590]again comparably sized capital city,
[00:04:11.920]so you still have state legislatures that meet here,
[00:04:15.480]it turned up four times as many hits
[00:04:19.960]for the word nitrate in the Lincoln Journal Star,
[00:04:24.440]but by searching the Des Moines Register,
[00:04:27.330]we had a whopping 613 hits,
[00:04:30.300]so almost an order of magnitude more times
[00:04:33.410]in the Des Moines Register than in
[00:04:35.290]the Wisconsin State Journal for the word nitrate.
[00:04:38.690]And so I feel like I really ended up
[00:04:41.520]in the perfect place because I can walk
[00:04:43.240]down the street in Des Moines,
[00:04:44.940]and I don't often randomly spout about nitrate,
[00:04:48.060]but if I were, there'd be people who might
[00:04:50.110]be interested in what I was saying.
[00:04:51.810]So that's really fantastic as a biogeochemist
[00:04:54.530]to be somewhere where at least thinking
[00:04:56.900]about biogeochemistry and these molecules
[00:04:59.240]that are in the environment that affect us
[00:05:00.883]is fresh on peoples' minds.
[00:05:04.210]Then while thinking about what sort of outline
[00:05:06.060]I should have for my talk,
[00:05:07.130]I just happened to notice this screen clip
[00:05:08.970]I took from the Des Moines Register
[00:05:10.410]and really these three articles
[00:05:11.930]that happened to pop up, happened to kind of
[00:05:14.230]align with my talk.
[00:05:15.655]And so first I wanted to discuss
[00:05:17.630]a little bit about the social, economic,
[00:05:19.360]and ecological consequences of nitrate.
[00:05:21.830]You can see here there's one article
[00:05:23.350]about how the Des Moines Water Works
[00:05:25.080]is planning a 15 million dollar expanded nitrate facility.
[00:05:29.850]Secondly, I want to talk a little bit
[00:05:31.560]about the Des Moines Water Works lawsuit,
[00:05:33.820]so how do we fix Iowa's nitrate pollution?
[00:05:36.030]Well is litigation an effective solution,
[00:05:39.010]so we'll look at that lawsuit in finer detail.
[00:05:43.910]And then, third, my research
[00:05:46.200]as a stream and river biogeochemist,
[00:05:48.980]here there was an article from earlier this year in 2018
[00:05:52.300]that says weather is a huge factor in nitrate levels
[00:05:55.110]and that is what my research has investigated as well,
[00:05:59.690]is are nitrate dynamics driven more
[00:06:01.540]by land use or season to inform
[00:06:05.100]what is the conversation around nitrate in Iowa.
[00:06:10.690]So as a little background we know
[00:06:12.390]that agriculture and water quality in the Midwest
[00:06:14.899]are intimately linked.
[00:06:17.210]Here we can see a map of the bushels of corn
[00:06:20.550]that were produced and you can see the Corn Belt there
[00:06:23.310]highlighted from Nebraska going west
[00:06:25.810]towards Indiana and Ohio, affectionately,
[00:06:28.700]my PhD advisor called those the vowel states,
[00:06:31.040]Iowa, Illinois, Indiana, Ohio,
[00:06:33.250]where a lot of our corn is produced.
[00:06:36.380]Because all that corn is produced there
[00:06:37.830]we have some of the higher nitrogen fertilization
[00:06:41.892]amounts as well, so you can see again,
[00:06:44.360]eastern Nebraska, Iowa, Illinois, and western Indiana
[00:06:49.020]have very high amounts of nitrogen fertilizer applied
[00:06:53.548]and then if we were to look at accumulative,
[00:06:55.910]a map that shows accumulative concentration
[00:06:57.980]of nitrogen in the Mississippi River watershed,
[00:07:01.630]we can see that the amount of nitrate in the water
[00:07:06.150]is increasing as it flows through the Corn Belt
[00:07:09.082]towards the Mississippi River again this is showing
[00:07:11.720]accumulation of nitrogen which is
[00:07:13.640]why it looks much redder along the Mississippi River
[00:07:17.030]but you can see that these states in the Corn Belt
[00:07:20.470]are contributing a fair amount of that nitrogen
[00:07:22.860]to the total amount.
[00:07:26.080]So what is Iowa's role in all of this?
[00:07:29.100]Iowa likes to tout itself as being
[00:07:30.820]number one in a lot of things,
[00:07:32.550]and it was just ranked last year
[00:07:34.640]in the US News and World Report
[00:07:36.050]as being number one in the state for best states,
[00:07:38.360]though there's some questions
[00:07:39.500]as to how they were determined,
[00:07:41.710]but they were looking at economic growth factors,
[00:07:43.880]transportation, livability, et cetera,
[00:07:47.060]so Iowa is number one in that,
[00:07:48.710]but in that same article they made a point
[00:07:51.810]to state that, "make no mistake, Iowa is a farm state."
[00:07:56.650]So we are also number one in raising more hogs
[00:07:59.380]than any other state, and we lead the nation
[00:08:01.720]in corn-growing, producing a fifth
[00:08:04.340]of US corn in the year 2016.
[00:08:08.140]One consequence of being such
[00:08:10.360]an agriculturally-dominated state,
[00:08:12.500]is we are also sadly number one in
[00:08:15.100]the amount of land that has been converted by humans
[00:08:18.010]from its natural land cover.
[00:08:19.870]You can see the top of the slide here
[00:08:21.380]indicates that greater than 97% of Iowa
[00:08:24.370]has been modified by humans in the last 150 years.
[00:08:28.080]These two maps show that contrast very clearly,
[00:08:31.070]the map on the left is showing Iowa land-cover
[00:08:34.310]in the 1850s, the light green there
[00:08:36.940]that is really pervasive is prairie,
[00:08:39.870]the darker green is forest,
[00:08:41.570]and you can see a lot of wetlands
[00:08:43.440]in the north-center part of the state.
[00:08:46.720]When we look at that same satellite data from 2002,
[00:08:51.080]we can see that there is a lot of cropland
[00:08:53.580]and there is some remnant prairie
[00:08:56.950]but much of the prairie that is there has been
[00:08:59.514]reconstructed or restored,
[00:09:02.530]and the pink here is of course urban areas.
[00:09:06.710]So Iowa's number one in some good things socially
[00:09:12.308]and some things that are impactful
[00:09:14.400]to the environment as well.
[00:09:16.380]So what are the social, economic, and ecological issues
[00:09:19.410]around nitrate here in the state,
[00:09:21.060]or next door in the state of Iowa?
[00:09:26.050]One major concern socially is drinking water quality,
[00:09:29.200]so here we can see our map of the United States
[00:09:31.770]showing the areas at risk of nitrate contamination
[00:09:35.460]in shallow groundwater.
[00:09:36.900]Again Nebraska has high nitrate concentrations
[00:09:40.830]as well as Iowa and other parts of the Midwest,
[00:09:43.910]giving that this is a groundwater map though
[00:09:45.660]you can see that Iowa and Kansas is
[00:09:47.467]a little bit more red than the other parts of the Midwest.
[00:09:51.410]And there are many articles that appear frequently
[00:09:55.320]in the Des Moines Register about nitrate levels
[00:09:58.810]and the reason I bring this one up
[00:10:00.950]is this one is from November of 2014,
[00:10:04.900]and the reason that this is important is that,
[00:10:06.770]often times nitrate levels peak in the spring,
[00:10:10.150]and here in the year 2014 nitrate levels
[00:10:13.430]were peaking very late in the year,
[00:10:15.471]so thinking about how things shift,
[00:10:19.010]and another reason to bring up this article
[00:10:23.000]is that if you, I don't often go down
[00:10:25.390]and look at the comments that are posted about articles,
[00:10:28.450]but I think that this shows some of the conflicts
[00:10:32.140]given these water issues in the Midwest,
[00:10:34.920]you can see this first comment here,
[00:10:37.240]by person C.K.S. is really curious
[00:10:41.690]about what this means for them and their personal health,
[00:10:45.440]they're concerned about how much water
[00:10:47.460]they can consume, or perhaps you can tell everyone
[00:10:50.610]what will happen if they drink contaminated water,
[00:10:52.920]what parts of their city are at risk,
[00:10:55.480]so this person is very concerned
[00:10:57.121]about this report that nitrate levels are peaking,
[00:11:00.730]and then you can see someone has a comment
[00:11:03.090]that doesn't help our conversation at all,
[00:11:04.970]but expresses this sentiment of some people,
[00:11:08.027]"thanks for the poison Mr. Farmer
[00:11:09.637]"so that you can make more money,"
[00:11:11.830]of course that doesn't help the conversation at all,
[00:11:14.460]pointing fingers and placing blame,
[00:11:16.330]but I think it presents the issue
[00:11:19.250]that people think this is a one-sided issue
[00:11:21.810]and really it's quite multifaceted.
[00:11:27.400]So there are social consequences of high nitrate,
[00:11:31.220]there have been links to different forms of cancers
[00:11:34.810]and pancreatic problems as well as immunological
[00:11:37.640]and microbiome impacts and as I discussed
[00:11:41.020]with the grad students earlier today,
[00:11:42.410]I shouldn't even mention blue baby syndrome
[00:11:44.440]because I think too many people latch onto that,
[00:11:46.913]Iowa has not had a reported case of blue baby syndrome
[00:11:49.450]since 1979 so it can be very serious and life-threatening,
[00:11:53.440]but not in the recent past,
[00:11:56.930]it's more so a chronic issue if you drink
[00:12:00.230]water with high nitrate.
[00:12:02.440]So what about economically?
[00:12:04.810]So again I said that Iowa is a farm state
[00:12:07.150]as was pointed out in that article,
[00:12:08.870]and in some data from the previous census,
[00:12:12.580]so a little bit old now,
[00:12:13.830]is that in the workforce, one in six Iowans
[00:12:17.050]are employed in the agricultural sector,
[00:12:19.150]and it netted $72.1 billion to the economy
[00:12:23.440]over a quarter of Iowa's economy,
[00:12:25.450]and when you look at cash receipts from
[00:12:27.496]agriculture, Iowa is second only behind California,
[00:12:31.810]and Nebraska comes in a close third,
[00:12:34.110]with 6.2% of all
[00:12:38.210]agricultural cash receipts coming from this state here,
[00:12:41.422]and 8.1% coming from Iowa.
[00:12:43.853]So agriculture is a very important driver
[00:12:46.610]of the economies of these Midwestern states,
[00:12:48.750]however there's also another economic cost,
[00:12:51.220]Iowa being number one in a lot of ways,
[00:12:53.380]we also have the world's largest nitrate removal facility
[00:12:57.270]at the Des Moines Water Works,
[00:12:58.810]So this is showing the tanks that remove nitrate
[00:13:02.270]when our source water is in exceedance
[00:13:04.928]of the 10 milligram per liter EPA drinking water standard,
[00:13:08.580]and you can see that there's a real economic cost to this,
[00:13:11.730]eight to 10 thousand dollars per day
[00:13:13.550]to run this nitrate removal facility in 2015,
[00:13:17.000]which is why that article that I had from 2014,
[00:13:21.010]there was exceptionally high levels of nitrate then,
[00:13:24.792]the ratepayers in the Des Moines metro
[00:13:28.330]paid $1.5 million and currently the city
[00:13:32.300]is looking for 15 million additional dollars
[00:13:35.280]to construct an even larger nitrate removal facility.
[00:13:39.410]So these are some very real costs
[00:13:41.120]that are currently being borne by the ratepayers
[00:13:47.300]in Des Moines.
[00:13:49.590]So finally the ecological issues related to high nitrate.
[00:13:53.980]There aren't many direct ecological issues
[00:13:56.910]here in the Midwest but rather what happens
[00:13:58.840]when that nitrate goes downstream
[00:14:00.730]in the Mississippi River.
[00:14:02.300]So in 2017 the dead zone that forms
[00:14:07.200]annually in the Gulf of Mexico
[00:14:09.870]was the largest it has ever been,
[00:14:12.140]it was the size of New Jersey,
[00:14:14.900]and if we look at some previous data here
[00:14:17.340]from the USGS going back a decade and a half,
[00:14:20.580]we can see that the flux of nitrate
[00:14:23.760]from the Midwest, which are those blue bars,
[00:14:26.060]is correlated to the area, the hypoxic zone,
[00:14:29.890]which is that dark-blue line.
[00:14:37.100]And nitrate has even farther-reaching effects
[00:14:40.600]than just the Gulf of Mexico,
[00:14:41.940]this is similarly interesting satellite data
[00:14:44.440]from NASA and what you can see
[00:14:48.150]here these red arrows are pointing out
[00:14:50.380]the stream of the Mississippi River,
[00:14:52.080]so freshwater and the density differences
[00:14:54.980]with the seawater don't mix immediately,
[00:14:58.890]and so you can see the plume of the Mississippi River
[00:15:01.350]flowing through the Gulf,
[00:15:02.970]and then this box here is zoomed in five days later,
[00:15:07.370]you can see the yellow arrows here
[00:15:09.050]are still indicating where this plume of freshwater
[00:15:11.460]from the Mississippi is flowing around the Florida Keys
[00:15:14.750]and eventually even up into the Gulf Stream,
[00:15:17.360]again here this yellow box in the top image
[00:15:20.450]is showing where this is, this is again five days later,
[00:15:23.600]and it shows that the Mississippi River
[00:15:26.010]that freshwater stream is just finally
[00:15:28.140]now being diluted as it heads through
[00:15:29.860]the middle of the North Atlantic
[00:15:31.970]which is pretty impressive but it's important to think
[00:15:34.730]that the Mississippi River has far-reaching impacts
[00:15:38.010]even beyond the Gulf directly.
[00:15:43.690]So what is Iowa's role in
[00:15:46.810]the contribution of nitrate to the Gulf?
[00:15:49.940]We can see that the Mississippi River is quite large,
[00:15:52.260]it covers parts or
[00:15:56.330]all of 32 states in the US,
[00:15:58.945]as well as two Canadian provinces,
[00:16:04.187]and so Iowa only represents about 4.5% of the land area,
[00:16:08.920]but a paper that was just put out
[00:16:10.450]by some colleagues at the University of Iowa
[00:16:13.850]found that Iowa contributes almost a third
[00:16:16.920]of the nitrate to the Gulf on any given year,
[00:16:19.940]and here's some data from that,
[00:16:21.160]this was a paper that came out in April,
[00:16:23.990]what this shows is,
[00:16:26.560]Iowa's fraction along the y-axis,
[00:16:29.670]the red dotted line there is our proportion
[00:16:32.780]of the Mississippi River watershed, 4.5%,
[00:16:35.560]you can see the blue bars are the fraction
[00:16:37.900]of water that Iowa is contributing to the Gulf,
[00:16:41.290]and the green bars are the fraction of nitrate
[00:16:44.290]that Iowa contributes to the Gulf.
[00:16:46.060]So you can see on an especially high year like 2016,
[00:16:49.490]over 40% of the nitrate going to the Gulf
[00:16:53.810]was estimated to come from Iowa,
[00:16:56.100]and on average it's just under 30%.
[00:16:59.570]So really high levels coming from Iowa.
[00:17:04.060]And here's a map of the 2016 data
[00:17:06.220]showing how deep red Iowa and southern Minnesota
[00:17:09.150]are to contributing to the Gulf of Mexico nitrate levels.
[00:17:16.060]So how do we try to fix the problem or address the problem?
[00:17:20.530]In 2015, just coming off some of those
[00:17:22.600]really high concentrations,
[00:17:24.410]the Des Moines Water Works chose litigation
[00:17:28.140]as one means of addressing the issue.
[00:17:32.160]So the Safe Drinking Water Act,
[00:17:33.880]which was passed in 1974,
[00:17:36.500]stated that water utilities must comply
[00:17:38.640]with certain drinking water standards,
[00:17:39.980]so Des Moines Water Works is required to
[00:17:43.270]have water be less than 10 milligrams per liter
[00:17:46.006]in terms of nitrate.
[00:17:49.200]Around the same time the Clean Water Act
[00:17:50.930]was passed two years earlier that,
[00:17:53.640]clearly defined point source polluters
[00:17:55.809]and point source pollution and stated
[00:17:58.830]that they must obtain a permit,
[00:18:00.380]either a general permit or a specific permit,
[00:18:03.120]to meet certain drinking water criteria.
[00:18:08.190]And Des Moines Water Works brought the lawsuit
[00:18:11.340]because they're needing to,
[00:18:13.430]due to the Safe Water Drinking Act,
[00:18:15.030]they're required to have water
[00:18:16.960]that's at a 10 milligram per liter or less level,
[00:18:20.226]however they felt that these counties upstream
[00:18:25.750]that have tile drainage,
[00:18:28.680]were not being addressed and the Clean Water Act
[00:18:32.010]was providing an exemption
[00:18:33.920]that should not have been provided to drainage districts.
[00:18:38.960]Which leads to the question,
[00:18:40.730]are all pipes and their effluent considered equal?
[00:18:44.980]So the larger image here and on the left,
[00:18:48.890]shows pipes coming from a tile drained field,
[00:18:52.400]and on the right is the water treatment facility
[00:18:54.670]at Des Moines.
[00:18:56.470]So the water that's being discharged
[00:18:58.400]from the water treatment facility
[00:19:00.040]is required to meet very specific
[00:19:02.350]concentrations of nutrients and contaminants,
[00:19:05.270]whereas all of these pipes that you see
[00:19:07.060]in an agricultural landscape of tile drainage
[00:19:10.010]have no such requirements to meet.
[00:19:14.660]And if you read the passage from the 1972 Clean Water Act,
[00:19:18.980]about what point source is defined as,
[00:19:21.680]you can see that Congress clearly defined it as
[00:19:25.997]"any discernible, confined and discrete
[00:19:28.167]"conveyance, including but not limited to
[00:19:30.817]"any pipe, ditch, channel, tunnel,
[00:19:32.737]"conduit, well, discrete fissure, container,
[00:19:34.687]"rolling stock, concentrated animal feeding operation,
[00:19:36.827]"or vessel or other floating craft,
[00:19:39.487]"from which pollutants are or may be discharged."
[00:19:42.290]That sounds like a lot of things
[00:19:44.070]could be a point source, right?
[00:19:46.080]But then you read the last sentence.
[00:19:48.467]"This term does not include agricultural stormwater
[00:19:51.427]"discharges and return flows from irrigated agriculture."
[00:19:56.210]So this exemption is agricultural stormwater discharge.
[00:20:02.310]As stream and river ecologists
[00:20:05.250]we often struggle defining what's base flow,
[00:20:07.930]what's storm flow, how can we tell
[00:20:10.020]what one discharge is over another,
[00:20:11.910]so we as scientists struggle and somehow Congress
[00:20:15.110]came up with this phrase, agricultural stormwater discharge.
[00:20:19.290]It's important to point out that this is not
[00:20:21.040]a government term, this isn't defined anywhere
[00:20:23.420]in any government documents,
[00:20:25.010]and if you chatted with any stream ecologist,
[00:20:28.510]it would be difficult to specify
[00:20:30.800]that as a scientific term as well,
[00:20:33.760]and in short, in 1972 when the Clean Water Act
[00:20:38.530]was written, Congress, not wanting to deal with
[00:20:43.490]all the senators and concerns of the agricultural Midwest,
[00:20:46.680]wanted to put this exemption in place
[00:20:48.820]because we had rivers catching on fire,
[00:20:51.350]we had industries dumping pollution
[00:20:53.270]directly into waterways, and so they needed something,
[00:20:56.700]but they didn't want to deal with everything quite yet.
[00:21:00.340]Of course here we are now almost 50 years later,
[00:21:03.400]and this phrase is still not defined anywhere.
[00:21:07.790]Nor has any court ever defined it.
[00:21:13.250]So what's the historical context
[00:21:14.910]for high nitrate in Iowa?
[00:21:18.770]Here's a geologic map of the state
[00:21:20.730]and you can see this large green lobe
[00:21:24.060]that dips down into the state from the north,
[00:21:26.870]and that's called the Des Moines Lobe,
[00:21:28.350]which is the area of the state
[00:21:30.890]that was glaciated during the last glaciation.
[00:21:34.600]The three squares you see in the upper left
[00:21:37.400]are the three counties that have the drainage districts
[00:21:41.080]that Des Moines Water Works was suing,
[00:21:43.680]and you can see Des Moines is down here at this black star.
[00:21:47.010]In fact if you ever drive through Des Moines on I-235
[00:21:49.960]you might see the capitol building
[00:21:51.560]sitting up on top of the hill,
[00:21:53.180]that hill is the terminal moraine
[00:21:54.620]of the last glaciation.
[00:21:59.500]And so because this area was covered in a glacier,
[00:22:04.416]it was a prairie pothole.
[00:22:07.230]Alright, there's those prairie potholes,
[00:22:08.940]so if you look at it from an aerial view
[00:22:10.530]you can see that the areas that still have
[00:22:12.630]this prairie pothole feature are very wet landscapes,
[00:22:15.950]and this is because the glacier flattened
[00:22:18.870]that area and then rain simply collects on it
[00:22:22.240]flowing to the lowest point but of course
[00:22:24.260]this landscape is very low all around.
[00:22:28.030]And so if we look at another map
[00:22:30.610]that shows the drainage districts of Iowa,
[00:22:33.200]we can see that the areas of Iowa
[00:22:35.190]that are tile drained really fit
[00:22:37.540]that same geologic feature the Des Moines Lobe.
[00:22:42.070]And you can see the abundance
[00:22:45.310]of drainage districts there.
[00:22:47.090]So the defendants in this lawsuit
[00:22:49.430]brought by the Des Moines Water Works
[00:22:50.890]were 13 different drainage districts
[00:22:52.900]in northwest Iowa, again just 13 of the many
[00:22:56.550]that are in those three highlighted counties.
[00:22:59.290]And again I put the black star on there
[00:23:01.430]to give you a reference as to where Des Moines is.
[00:23:04.230]It's the amount of work that went into constructing
[00:23:07.360]these drainage districts 100 years ago
[00:23:12.330]You can see that in this image,
[00:23:14.200]there's a house on the ditch digger,
[00:23:17.510]and from stories that I've heard
[00:23:19.330]from the Iowa State Historical Society,
[00:23:21.890]families would live in those houses
[00:23:24.500]and the children of those families
[00:23:27.158]would shift school districts from year to year
[00:23:30.780]as the drainage ditch digger was moving
[00:23:34.710]from one school district to the other
[00:23:36.930]as it made these ditches across the landscape.
[00:23:41.170]So drainage districts,
[00:23:42.003]just to give you a little background on them,
[00:23:43.710]they're established under Iowa law,
[00:23:45.780]and they're local governments that spread costs
[00:23:48.500]evenly throughout the drainage district.
[00:23:50.580]They are immune under Iowa law from lawsuits for damages,
[00:23:54.570]and no Iowa case has ever addressed
[00:23:57.000]whether an injunctive could be issued.
[00:23:59.280]There's gonna be times throughout this talk
[00:24:01.340]where I sound like a lawyer but I'm not,
[00:24:03.270]but I have had some of the lawyers
[00:24:05.840]from the group that represented Des Moines Water Works
[00:24:09.890]speak to my class about this,
[00:24:11.670]so I give credit for my scant legal knowledge
[00:24:14.570]to my colleague John Lande at Dickinson law firm.
[00:24:19.020]So an injunctive is when a judicial process
[00:24:22.487]requires a person or persons to refrain
[00:24:27.060]from doing a particular act, or to do a particular act.
[00:24:30.370]So the drainage districts have never been told
[00:24:33.020]you need to do or not do something in particular.
[00:24:39.370]So why was Des Moines Water Works
[00:24:41.850]suing these three counties?
[00:24:43.380]Well they argued that drainage districts are point sources,
[00:24:48.770]and they attempted to define
[00:24:50.850]what has never been defined before,
[00:24:52.410]agricultural stormwater drainage,
[00:24:53.970]by saying that applies to runoff,
[00:24:56.280]whereas nitrate is being transported
[00:24:58.780]by groundwater under the ground,
[00:25:01.100]not by surface water runoff,
[00:25:02.970]So therefore it does not fall under
[00:25:04.950]the exemption of agricultural stormwater discharge.
[00:25:08.620]Further, they felt that the
[00:25:13.040]federal and state constitutions
[00:25:15.528]they prohibit total immunity for the drainage districts.
[00:25:22.180]So the one question that was lingering
[00:25:24.290]just as this lawsuit was brought,
[00:25:25.870]of course is why us?
[00:25:27.580]So this lawsuit was just directed
[00:25:29.720]at 13 different drainage districts in these three counties,
[00:25:35.608]and so why those 13 drainage districts,
[00:25:39.040]and secondly, another question,
[00:25:41.870]was why us because Des Moines is 200 river miles away?
[00:25:45.620]Why is that our nitrate, how do you know,
[00:25:48.020]why isn't it from the suburbs of Des Moines, or even closer?
[00:25:53.520]And so that was right when I arrived in Des Moines
[00:25:56.100]to start my position at Drake,
[00:25:57.990]and I felt like well those are
[00:25:59.690]some low hanging fruit questions
[00:26:01.900]that I could address with my research program.
[00:26:04.820]And so the data that I wanted to share with you today,
[00:26:10.377]are two questions that I ask
[00:26:11.950]related to the lawsuit, or at least some of
[00:26:15.527]the questions that were swirling around the lawsuit.
[00:26:18.210]And I was curious whether or not
[00:26:20.290]nitrate dynamics in the Raccoon
[00:26:22.230]were driven more strongly by differences
[00:26:24.170]in land-use or seasonal changes,
[00:26:26.450]as you can see in this map,
[00:26:27.960]the Raccoon actually has three branches,
[00:26:30.580]the counties that were in the lawsuit
[00:26:32.670]are on the north Raccoon,
[00:26:34.130]but there's also a middle and a south branch
[00:26:36.600]that all converge about 30 miles west of Des Moines.
[00:26:41.180]And then secondly, I wanted to ask,
[00:26:43.860]how much nitrate is lost via denitrification
[00:26:46.521]in the river, could that nitrate
[00:26:48.500]conceivably travel 200 miles from these drainage districts
[00:26:52.370]to the city?
[00:26:56.440]So here's the Raccoon River watershed,
[00:26:58.910]again as I mentioned you can see
[00:27:01.130]in the state map of Iowa, the geologic map
[00:27:04.470]that most of the watershed falls on that Des Moines Lobe,
[00:27:07.920]and that's largely the north watershed that you see here,
[00:27:11.270]then there's also the middle and south watersheds,
[00:27:14.510]a lot of it is crop and pastureland,
[00:27:19.030]and the slope or gradient of the watershed varies
[00:27:22.070]from just 2.5% throughout the entire north
[00:27:24.880]'cause that's a very flat area,
[00:27:26.550]to 5.1% in the middle, and an almost 10% slope
[00:27:29.978]across the watershed in the south.
[00:27:32.640]The overall average for the slope
[00:27:34.410]in the watershed is 4%.
[00:27:38.080]And here you can see how the agriculture
[00:27:39.960]varies across these three different sub-basins.
[00:27:44.800]So the cropland is the most pervasive,
[00:27:49.260]you can see that it varies
[00:27:50.810]in the smallest amount,
[00:27:57.070]In the south, the crop represents 56%
[00:28:03.030]of the watershed area whereas pasture is 26%,
[00:28:07.300]and up in the north it's 86% crop,
[00:28:10.950]and only 2% pasture.
[00:28:14.780]Overall, it's roughly 76% cropland
[00:28:19.800]and 6% pasture.
[00:28:24.000]So we have some variation in the different sub-basins.
[00:28:26.720]So what I did with several of my students
[00:28:28.880]is sample nine different locations
[00:28:30.710]throughout the lower Raccoon River watershed
[00:28:32.919]throughout the year.
[00:28:35.520]We sampled these nine sites every two weeks for 18 months,
[00:28:39.840]and we also did a spatial snapshot
[00:28:41.970]which that image from my title slide represents.
[00:28:45.310]Here we are sampling a tributary
[00:28:46.930]both in May, during high flow, with a motorboat,
[00:28:49.800]and then later in July at lower flow with canoes
[00:28:55.150]to give ourselves a spatial snapshot
[00:28:58.066]of all the tributaries and multiple points
[00:29:00.000]along the mainstem of the river.
[00:29:02.000]So we measured multiple things
[00:29:03.350]including water chemistry and suspended sediment
[00:29:05.590]in terms of ecosystem structure,
[00:29:07.480]as well as microbial denitrification rates
[00:29:09.620]in terms of ecosystem function,
[00:29:11.610]to try to understand how water quality
[00:29:13.390]varies with season and land use.
[00:29:16.320]So I had a great team of undergraduates
[00:29:18.300]assist me with this, in all sorts of weather,
[00:29:20.720]so here's one of our sites on a beautiful sunny day,
[00:29:23.666]more wet summer day, and then of course,
[00:29:26.517]also in the middle of January
[00:29:28.310]when we had to filter in the car,
[00:29:30.400]lest the filter freeze before we could sample it.
[00:29:35.170]So I wanted to show you a little bit of the data now,
[00:29:37.630]the way that I arranged this figure
[00:29:39.130]is how I'll present all the data,
[00:29:40.670]so I'll just give you a minute
[00:29:43.360]to digest it.
[00:29:44.690]As you can see here the nine sites along the Raccoon,
[00:29:48.820]so the two yellow sites are in the north,
[00:29:51.060]coming down, the north Raccoon River watershed,
[00:29:54.610]and those are represented here by north 21,
[00:29:57.340]these are the mile markers and north Raccoon two.
[00:30:00.640]The blue are the middle and the south Raccoon
[00:30:03.170]flowing in from the west,
[00:30:04.990]going from just before the confluence
[00:30:07.910]in the middle and the south,
[00:30:09.200]to mile marker 15 and mile marker one,
[00:30:12.870]and then three sites along the mainstem
[00:30:15.010]as the Raccoon flows into Des Moines,
[00:30:16.810]which is represented by the red urban land cover here.
[00:30:20.920]So what we can see in terms of nitrate concentration,
[00:30:23.890]is that it did peak in the spring,
[00:30:26.210]we had a strong seasonal effect,
[00:30:27.660]so you can see that across all nine sites,
[00:30:29.670]there's a peak in the spring,
[00:30:31.200]and if we were to animate in the,
[00:30:33.910]uh oh I hope I didn't freeze it.
[00:30:40.980]So if we were to animate in the
[00:30:42.860]10 milligrams per liter, eight of the nine sites
[00:30:45.750]exceeded 10 milligrams per liter
[00:30:47.930]at some point during the year in the spring.
[00:30:52.180]And I'm just having to restart again.
[00:30:58.585]So now I'd like to point out that we're caring for Clinton.
[00:31:05.270]I have that up here, should I escape out of that?
[00:31:14.490]Oh I can't see that over here.
[00:31:46.380]There it is.
[00:31:54.720]Alright, are we good, great.
[00:31:58.360]There's the 10 milligrams per liter,
[00:32:00.330]so you can see all sites except this,
[00:32:04.002]the one branch on the south Raccoon here,
[00:32:07.020]did exceed 10 milligrams per liter
[00:32:09.070]in the late spring, early summer.
[00:32:12.780]However this only tells part of the story, right,
[00:32:14.890]because the concentration does not
[00:32:18.260]take into account discharge, the different sizes
[00:32:20.870]between these different branches,
[00:32:22.570]and so I also calculated the export of nitrate,
[00:32:25.960]or the actual mass leaving the system through time
[00:32:29.930]at all of these sites, and you'll notice,
[00:32:32.140]especially if you look at the blue sites
[00:32:35.190]between concentration and export,
[00:32:37.230]we now see that the south and the middle
[00:32:39.810]are contributing very little nitrate downstream,
[00:32:44.010]whereas the high concentrations in the main stem,
[00:32:46.870]those red sites, are really being driven by the north.
[00:32:50.190]You can see high levels, especially in the spring,
[00:32:52.809]throughout the two sites in the north
[00:32:55.550]and then that continues down the main stem in the red.
[00:32:58.230]So we found both a very significant effect of season,
[00:33:00.640]very high in the spring,
[00:33:02.300]also a significant effect of site.
[00:33:07.440]However if you remember the watershed map,
[00:33:10.500]the north was much larger than the middle and the south,
[00:33:13.660]and so one final calculation here
[00:33:15.820]is to think about the export
[00:33:19.570]divided by watershed area to give us a yield,
[00:33:22.300]how much nitrate is coming from by hectare,
[00:33:24.870]or square kilometer, of the watershed?
[00:33:28.690]And when I calculated yield,
[00:33:30.400]I found that again, season was a strong effect,
[00:33:33.130]highest in the spring, but now we see
[00:33:35.320]that the site effect is no longer significant.
[00:33:40.030]And you can see that there's sites along the south
[00:33:42.700]that have nearly equal yields to the north
[00:33:47.490]and the main stem.
[00:33:53.570]So then I wanted to see what predicts
[00:33:55.930]the concentration export and yield across the watershed,
[00:33:58.980]is it something related to the watershed,
[00:34:01.060]or is it something related to land use?
[00:34:03.250]So some interesting calculations
[00:34:05.340]that our colleagues suggested were to look at
[00:34:07.590]the concentration-discharge relationships.
[00:34:10.890]So here you can see those nine sites again,
[00:34:13.400]and I analyzed the
[00:34:18.130]concentration data based on the flow
[00:34:22.370]that was occurring, so we can see along
[00:34:24.420]the x-axis now is discharge,
[00:34:28.000]and I found significant relationships
[00:34:30.550]only up to the median discharge
[00:34:33.030]of the 18 month period.
[00:34:35.270]Whereas in flows that exceeded the median discharge,
[00:34:40.010]cue 50, we see that there is no significant relationship
[00:34:43.350]at any of the sites.
[00:34:45.150]So what these data suggest,
[00:34:47.330]is that at low flow, as discharge increases,
[00:34:50.970]nitrate concentrations increase as well,
[00:34:54.200]but only to a point, at which point,
[00:34:57.120]higher discharges do not translate
[00:35:01.070]to equally higher nitrate concentration,
[00:35:03.100]so at some point we do get
[00:35:07.260]most of the nitrate off the landscape
[00:35:09.030]and higher discharges don't necessarily mean
[00:35:11.370]equally higher increases in nitrate concentration.
[00:35:19.220]Secondly I wanted to address
[00:35:20.480]what predicts the variation
[00:35:22.080]in both nitrate export and yield,
[00:35:23.910]and so the three watershed characteristics
[00:35:25.740]that I was interested in that varied
[00:35:27.100]across the landscape were slope,
[00:35:29.720]watershed area, and the proportion of cultivated crops.
[00:35:33.510]I will say that slope was correlated
[00:35:36.340]to both area and proportion of cultivated crops,
[00:35:38.980]but area and cultivated crops were not correlated.
[00:35:43.460]So here along the top we can see
[00:35:46.640]those three different watershed characteristics,
[00:35:48.640]and then we see the six seasons
[00:35:50.230]along the left side of the table.
[00:35:54.610]Regarding export, what we can see very clearly
[00:35:57.350]the strongest relationships here
[00:35:59.232]in any season were with watershed area,
[00:36:03.330]so the amount of nitrate that was being exported
[00:36:07.020]from the system didn't necessarily
[00:36:08.960]depend on cultivated crop area, or slope,
[00:36:12.330]but most strongly with the watershed area,
[00:36:14.770]so larger watersheds meant more nitrate,
[00:36:18.320]all of those were positive relationships.
[00:36:21.090]Regarding yield, we saw that
[00:36:24.970]in most seasons, watershed area again dictated yield,
[00:36:30.410]though at times the relationship was often negative,
[00:36:34.090]so larger watersheds had lower yield
[00:36:37.210]per square kilometer,
[00:36:39.250]but what I found really interesting
[00:36:40.590]is that in spring when we saw the highest concentration,
[00:36:43.390]highest export, highest yield,
[00:36:45.480]we see that the nitrate yield
[00:36:49.210]from each of these subwater sheds,
[00:36:51.290]was most strongly related to the slope
[00:36:53.167]and the proportion of cultivated crops,
[00:36:55.930]and in a negative relationship with slope,
[00:36:58.360]so as slope increased, the yield of nitrate decreased.
[00:37:05.510]So in conclusion to this first research question,
[00:37:08.600]the agricultural land did contribute
[00:37:10.570]similarly to these nitrate dynamics,
[00:37:13.160]and we see that the highest yields
[00:37:15.230]were from heavily cultivated areas in the spring,
[00:37:17.810]when we had that really high concentration,
[00:37:20.000]high export and high yield.
[00:37:24.550]So the last bit of the research I want to talk about
[00:37:28.580]was how much nitrate is lost via denitrification?
[00:37:32.900]Can nitrate travel 200 river miles
[00:37:35.880]to the city of Des Moines where
[00:37:38.060]it would need to be treated for drinking water?
[00:37:40.530]So a real brief primer on denitrification,
[00:37:43.360]that's a microbial process that permanently
[00:37:45.230]removes nitrogen from streams,
[00:37:47.330]there's several intermediate steps
[00:37:49.180]as nitrate is converted to dinitrogen gas,
[00:37:53.350]and we collected sediments in the field,
[00:37:55.840]we returned these sediments to the lab for sample analysis,
[00:37:59.720]and when your daughter's six she gets to come along too,
[00:38:02.486]and then what we did is we created these
[00:38:04.950]small micro habitats where we incubated sediments
[00:38:08.800]for a period of time and then measured
[00:38:11.020]the generation of nitrous oxide N2O,
[00:38:15.420]through time to estimate the denitrification rates.
[00:38:21.320]We did this at three of the sites on a monthly basis,
[00:38:24.430]and what we found is that
[00:38:26.200]there was a strong seasonal pattern,
[00:38:28.960]as you can see one site on the south Raccoon,
[00:38:31.190]one site on the north and one site on the main stem.
[00:38:34.230]You can see that rates were highest in the late summer
[00:38:37.670]and early fall of 2017.
[00:38:41.440]And there was a slight site effect,
[00:38:43.840]where the north Raccoon had higher denitrification rates
[00:38:46.910]than the south and the main stem.
[00:38:50.800]These rates were predicted by sediment organic matter
[00:38:53.350]and just to compare organic matter
[00:38:55.300]in these sediments, the sediment organic matter
[00:38:59.060]in the stream bottom was less than 1%, 0.66%,
[00:39:02.850]whereas the water column organic matter
[00:39:04.620]that we measured as well, was over 12%,
[00:39:07.680]so we're losing a lot of organic matter
[00:39:10.330]in this larger river in the stream water,
[00:39:12.430]and there's not much in the stream bed.
[00:39:17.770]We did amendments as well to determine
[00:39:20.090]whether or not these bacteria were nitrogen-limited,
[00:39:23.610]or carbon-limited, and what we found was that,
[00:39:28.240]looking at the ratio of the denitrification rates
[00:39:31.360]from amended sediments versus unamended sediments,
[00:39:34.570]many of the sites and dates overlap
[00:39:39.504]with the one-to-one ratio,
[00:39:42.160]suggesting that these microbes are not limited
[00:39:44.430]by either nitrate or carbon so,
[00:39:47.720]in most sites, in most dates,
[00:39:50.010]these bacteria are denitrifying at their maximum capacity.
[00:39:56.050]So finally to answer that question,
[00:39:59.240]can the stream and river process
[00:40:01.810]the nitrate as it travels downstream,
[00:40:04.350]such that the nitrate from these upstream counties
[00:40:07.820]is lost before the river reaches Des Moines Water Works,
[00:40:11.430]and as the title suggests, the answer is no.
[00:40:15.120]And if we look at just the main stem now,
[00:40:18.050]the Raccoon River at mile marker 30,
[00:40:20.790]the smaller plot here is the concentration of nitrate
[00:40:23.560]in the stream water, and the upper plot
[00:40:25.960]is the microbial denitrification rates,
[00:40:28.350]you can see that the lowest denitrification
[00:40:30.420]with the white arrow was in the spring,
[00:40:32.540]cold temperatures, and high flows,
[00:40:36.680]were limiting organic matter tension and microbial activity,
[00:40:40.540]whereas the highest denitrification rates
[00:40:42.750]were in the late summer, early fall.
[00:40:44.990]And this happened to correspond with
[00:40:47.320]the highest nitrate concentration
[00:40:49.330]was also when the microbes had the lowest
[00:40:51.750]denitrification rates and during
[00:40:54.380]the highest denitrification rates in the late summer,
[00:40:56.600]we also saw the lowest nitrate concentration.
[00:41:01.380]So in a way we have the best scenario in the summer,
[00:41:03.930]where we're gonna be able to take
[00:41:05.040]the highest proportion of nitrate
[00:41:07.120]out of that export, whereas in the spring,
[00:41:10.730]we're taking out only a little
[00:41:12.290]and the pool was much larger
[00:41:14.180]'cause it's high concentration.
[00:41:16.540]So if we take a look at these data,
[00:41:19.843]this is the uptake length of nitrate,
[00:41:22.760]so any hypothetical nitrate molecule
[00:41:27.330]will travel a median distance of
[00:41:30.020]3800 kilometers in the river,
[00:41:34.240]and I'll make a note that the Mississippi River
[00:41:37.310]is 3780 kilometers long so this is
[00:41:41.870]just 30 kilometers past the length of the Mississippi River
[00:41:45.300]is the median distance nitrate will travel
[00:41:50.611]before it's lost by denitrification.
[00:41:52.660]The shortest, in July, again those black arrows,
[00:41:55.400]sort of the ideal time as you can see,
[00:41:58.947]I'm not gonna turn on the laser pointer again,
[00:42:02.610]lest it freeze.
[00:42:03.721]The shortest distance was only 58 kilometers,
[00:42:06.830]so just over 30 miles, and the Raccoon River is
[00:42:10.220]over 200 miles long so at some times of year,
[00:42:13.620]the river can process the nitrate that's in it,
[00:42:16.430]however the median distance is much longer
[00:42:19.830]than the Raccoon and you can see
[00:42:21.850]it's at it's sort of worst case scenario in March
[00:42:24.560]when we have high nitrate concentrations,
[00:42:26.320]and low denitrification rates,
[00:42:28.010]the average nitrate molecule will travel
[00:42:30.430]over 13 million kilometers,
[00:42:34.480]and as a point of reference I add on here
[00:42:37.780]the large dash lines are the length
[00:42:40.300]of the Mississippi River, the small dash line
[00:42:43.090]is the length of the Raccoon River,
[00:42:45.080]so you can see that in about 50% of the cases,
[00:42:49.177]the nitrate molecules will travel
[00:42:51.230]farther than the Mississippi is long
[00:42:53.940]provided that no new nitrate enters the system,
[00:42:57.270]and just to put that longest time in perspective,
[00:43:00.500]it's 363,000 kilometers to the moon,
[00:43:03.810]so worst case scenario,
[00:43:06.510]the Raccoon River would have to flow to the moon
[00:43:08.390]and back about 18 and a half times
[00:43:14.200]to remove all the nitrate that's in it
[00:43:16.440]when the rates are that low.
[00:43:19.400]So the answer to whether or not
[00:43:22.893]nitrate can travel 200 river miles in the Raccoon River
[00:43:27.000]is that it surely can and there is not much
[00:43:31.600]nitrate lost by denitrification.
[00:43:35.110]So in conclusion coming back to the lawsuit,
[00:43:40.340]rather than the first law of motion here,
[00:43:41.960]of course the first law of anything
[00:43:44.020]environmentally related to the law
[00:43:47.420]is that a river on trial tends to stay on trial.
[00:43:49.870]The Water Works lawsuit was stifled
[00:43:53.060]two years after it was brought, so March 2017.
[00:43:58.690]And there was a question in the lawsuit
[00:44:00.520]to the Iowa Supreme Court at a state level
[00:44:02.440]and to a US District Court at a federal level.
[00:44:07.800]The Iowa Supreme Court had two of the seven justices
[00:44:11.060]recuse themselves, and therefore the majority
[00:44:14.970]of three justices stated that Des Moines Water Works' claims
[00:44:18.710]could not proceed and they relied on
[00:44:22.230]stare decisis, which is legal precedent,
[00:44:25.140]so no drainage district had been sued
[00:44:27.480]for such damages in the last 100 years,
[00:44:30.150]therefore, precedents demonstrates
[00:44:32.700]that these drainage districts cannot be
[00:44:36.640]held accountable now.
[00:44:38.740]They also relied on least cost avoidance,
[00:44:41.020]so least cost avoidance said
[00:44:42.470]that it was cheaper for Des Moines Water Works
[00:44:44.650]to treat water than it would be
[00:44:46.470]for the drainage districts to address the issue themselves.
[00:44:51.140]And then finally they stated that the legislature
[00:44:53.830]should act rather than have a legal court decision.
[00:44:59.120]What they did not consider though, in their decision,
[00:45:01.470]were effects outside of Iowa,
[00:45:03.120]so all those downstream effects,
[00:45:04.410]particularly the Gulf of Mexico hypoxia,
[00:45:06.820]nor did they consider public health effects,
[00:45:09.130]so they were trying to keep it limited
[00:45:11.060]to what economic burden there is
[00:45:13.586]to the agricultural community as well as
[00:45:17.350]to the ratepayers at Des Moines Water Works.
[00:45:21.020]However, one of the two justices
[00:45:23.420]who wrote the dissenting opinion,
[00:45:26.210]argued that the drainage district immunity
[00:45:28.090]was developed in a different era
[00:45:29.730]with a different scientific understanding,
[00:45:31.860]and in fact in the early 1900s fertilizer use
[00:45:34.640]was quite minimal relative to what it is today.
[00:45:39.450]They also pointed out that the purpose of law
[00:45:41.400]is to right wrongs, and in their opinion,
[00:45:43.650]pollution is a wrong,
[00:45:45.230]and that old cases never considered
[00:45:47.310]whether an injunction, again,
[00:45:49.090]whether a group or an entity could be
[00:45:52.060]told to refrain from doing something
[00:45:53.910]or to be required to act,
[00:45:56.130]that they felt that they could
[00:45:59.210]force drainage districts to act via an injunction.
[00:46:04.560]At the federal level,
[00:46:06.630]the US District Court stated
[00:46:09.160]that the federal court dismissed
[00:46:10.880]all of the federal law claims.
[00:46:12.890]They ruled that they had no power
[00:46:14.320]to order drainage districts to take action
[00:46:16.270]because drainage districts are under Iowa law,
[00:46:20.030]and that the state law did not give
[00:46:23.050]drainage districts power to remedy pollution,
[00:46:25.300]and so therefore the federal court could not order them to.
[00:46:28.090]So in a way this lawsuit ended up
[00:46:29.940]in the nebulous region between the federal government
[00:46:32.570]and the state government,
[00:46:33.770]where the federal government said,
[00:46:35.280]this is a state decision, and the Iowa Supreme Court said,
[00:46:39.890]this is a legislative decision, not ours.
[00:46:43.180]So I was feeling pretty excited
[00:46:46.010]how my research might actually inform
[00:46:48.420]a major case and in fact, had this been appealed,
[00:46:51.760]it may have gone up to the Supreme Court
[00:46:53.900]of the United States and I was maybe
[00:46:56.100]getting ahead of myself, thinking I'd be able
[00:46:57.830]to present some data to the US Supreme Court,
[00:47:00.810]and while that didn't happen,
[00:47:03.030]I was featured in Des Moines Water Works Water Line,
[00:47:06.980]in November 2017 for our work,
[00:47:08.910]which I guess is a distant consolation prize.
[00:47:14.040]But it'll be interesting to see
[00:47:15.780]what happens, this was a really unique case
[00:47:17.950]that was brought by the Des Moines Water Works,
[00:47:19.580]of course agricultural pollution does affect many of us,
[00:47:23.220]however thinking about how to address
[00:47:26.410]that is a very multifaceted issue
[00:47:29.090]that is gonna require a lot of creative thinking,
[00:47:31.620]and there is definitely not any single entity
[00:47:34.240]or industry to blame for this,
[00:47:36.700]whereas we do have to think creatively together.
[00:47:40.240]So I wanted to thank some of my colleagues,
[00:47:42.440]Amy Burgin and Terry Loecke at University of Kansas,
[00:47:45.810]Chris Jones at University of Iowa and Cari Davis,
[00:47:48.830]Angela Bowman at Iowa State,
[00:47:51.180]and then a host of Drake undergraduates
[00:47:53.330]who have helped along the way.
[00:47:56.460]And then finally we've received
[00:47:57.570]some funding from Des Moines Water Works,
[00:47:59.040]the Raccoon River Watershed Association,
[00:48:00.550]and Polk County Conservation,
[00:48:01.870]and we had some great citizen scientists
[00:48:03.950]help us out on those more intensive spatial sampling dates.
[00:48:08.120]So thanks very much and I'd be happy
[00:48:10.010]to answer any non-legal questions about that.
[00:48:20.090]Alright, anyone have a question?
[00:48:27.160]Well thank you Peter, wonderful talk,
[00:48:31.825]I read the news recently the nitrate
[00:48:33.510]is also big concern in Nebraska
[00:48:36.110]so it would be really interesting
[00:48:38.030]to do similar research in Nebraska.
[00:48:40.680]I would like to go back to the time series data
[00:48:44.490]that you showed with the
[00:48:48.500]yield per area?
[00:48:54.253]I'm also new to the nitrate area
[00:48:56.577]but I'm interested to learn what caused
[00:49:00.300]this seasonal change, are they related
[00:49:04.430]to the human fertilization activities,
[00:49:08.580]or are they driven by the amount
[00:49:11.900]of say precipitation?
[00:49:14.650]Would you just explain that-
[00:49:16.320]Yeah absolutely, I think,
[00:49:17.667]regarding that these highest yields in the spring
[00:49:22.492]are very likely, though I haven't measured
[00:49:24.360]the fertilizer application rates,
[00:49:25.660]very likely due to the fertilizer application
[00:49:27.580]occurring in early spring,
[00:49:30.400]followed by precipitation events at that time,
[00:49:32.670]or snow melt, or thawing of the soil,
[00:49:37.790]and so you can see that the south
[00:49:40.699]that has a lower cultivated crops here,
[00:49:45.890]it did have a lower yield in general,
[00:49:50.700]relative to the north which carried
[00:49:53.070]into the main stem so I would,
[00:49:57.243]I think that strongly indicates
[00:49:58.840]the fertilizer application as well
[00:50:00.760]as precipitation early in the spring.
[00:50:05.840]And one thing that's kind of interesting
[00:50:07.010]in Nebraska, so I've heard a lot of the fertilizer
[00:50:11.050]application will also happen in the fall
[00:50:13.230]when it's a bit cheaper.
[00:50:15.408]Which doesn't actually help this issue,
[00:50:16.250]because your plants aren't growing in the winter
[00:50:18.040]so they're not taking it up, and so yeah.
[00:50:23.300]Lots we can learn from Iowa.
[00:50:27.375](muffled voice speaking)
[00:50:40.478]Yeah so, you know,
[00:50:42.243]we are on the ET precipitation line right now,
[00:50:45.660]you know it kind of runs right through Lincoln,
[00:50:47.500]you irrigate to the west and drain to the east.
[00:50:50.450]So how would you expect, or could you speculate,
[00:50:53.440]how these sort of seasonal patterns
[00:50:55.030]would change when you go from drain systems
[00:50:58.530]to irrigated systems?
[00:51:00.870]And do you think it'd be,
[00:51:02.820]my assumption if it's me, well we know
[00:51:04.480]there's probably still seasonal patterns
[00:51:06.450]but maybe it'd be worth sort of speculating
[00:51:08.500]on sort of how'd you see things changing a little bit.
[00:51:11.910]Yeah I wonder if there'd be a more constant input
[00:51:16.680]from the groundwater or would that groundwater
[00:51:19.250]exchange 'cause what we found,
[00:51:20.710]what's interesting in our study
[00:51:23.980]is that we did span two fall periods,
[00:51:27.060]and the fall of 2017,
[00:51:30.030]which is the right side of these figures,
[00:51:34.090]was very low flow period
[00:51:38.171]relative to the previous fall of 2016,
[00:51:40.770]and so we see it very closely coupled
[00:51:44.980]with discharge, whereas I wonder if here,
[00:51:47.440]if surface water changes would
[00:51:51.860]not affect the nitrate concentrations as much.
[00:51:56.090]I still think you'd see some seasonal pattern
[00:52:02.233]with the application of fertilizer,
[00:52:03.330]but maybe it would be more muted
[00:52:06.430]in the spring, given the irrigation,
[00:52:10.190]but then maybe higher during periods of low flow
[00:52:13.270]where Iowa might see a real dip
[00:52:15.820]in nitrate export and yield,
[00:52:17.830]you might still be a little bit higher at that point.
[00:52:21.650]Would be my speculation.
[00:52:34.890]Thanks for the nice talk.
[00:52:37.050]You know, I mean farmers need drinking water too,
[00:52:41.010]but to look past that, I mean the simplistic
[00:52:45.220]view of this, this is more of a policy question,
[00:52:47.510]I mean you've got kind of a rural-city divide,
[00:52:52.250]which we've been talking about with politics recently,
[00:52:54.830]but the city people need their water
[00:52:59.300]cleaned and they're upset at the
[00:53:03.430]folks that are making it so it's not clean,
[00:53:06.760]I'm wondering if there's an opportunity
[00:53:11.603]to not to make those parties further apart
[00:53:17.130]but to draw them together in some kind of collaboration
[00:53:19.470]and I'm just wondering since you're in Des Moines,
[00:53:21.656]it always seemed to me that we could potentially,
[00:53:26.480]for example, have people downstream
[00:53:30.660]helping to pay for easements to put habitat,
[00:53:35.540]restore well-ends along farm edges,
[00:53:37.770]or grasslands that would help naturally
[00:53:40.370]kind of environmental design ways
[00:53:42.380]to take nitrates out before they get into
[00:53:44.970]the streams and rivers.
[00:53:46.310]But obviously that takes space away
[00:53:48.930]from high yield in cornfields and soybean fields,
[00:53:52.780]and it also takes money to input those.
[00:53:55.860]So I just wondered is there any talk
[00:53:58.400]about any kind of
[00:54:01.120]you know use of taxes or other kind of positive,
[00:54:06.970]not that taxes are positive but (laughs),
[00:54:09.710]any collaborations between the city
[00:54:12.190]and the rural people to try to solve the problem.
[00:54:16.110]Yeah, I think what is again, Nebraska, NRTs?
[00:54:20.300]Natural Resource Districts, yeah.
[00:54:21.260]NRDs, okay so, an analogous
[00:54:26.870]quasi-governmental framework in Iowa
[00:54:29.340]are watershed management authorities,
[00:54:31.520]and so those are defined by watershed boundaries
[00:54:34.530]rather than county, or municipal boundaries,
[00:54:37.890]where there's 22 throughout the state
[00:54:41.610]so they by no means cover the state
[00:54:43.500]but the north Raccoon is a WMA,
[00:54:45.980]and that gives the authority for a municipality
[00:54:50.410]to spend tax dollars elsewhere in the watershed.
[00:54:53.480]So exactly what you were talking about to try to
[00:54:57.090]remedy drinking water issues
[00:54:59.740]at a point of extraction further upstream,
[00:55:09.934]there's slow movement and progress on that
[00:55:11.260]because many of these WMAs have been established,
[00:55:13.820]but they aren't prescriptive,
[00:55:17.360]they allow for this collaboration,
[00:55:19.590]though they can't direct the management
[00:55:24.010]to occur, it has to be agreed upon
[00:55:26.120]by all members of the WMA.
[00:55:28.680]So it looks positive that things are
[00:55:31.030]moving that way, but,
[00:55:33.530]right now the scale of the issue is quite large.
[00:55:37.530]One thing that many people in Iowa
[00:55:40.970]often tout is how much area
[00:55:44.500]is in conservation, and in fact,
[00:55:46.770]Bill Northey is right now Undersecretary
[00:55:49.400]in the Department of Agriculture,
[00:55:50.790]he was our state Secretary of Agriculture
[00:55:53.770]before he was tapped to be Sonny Purdue's Undersecretary,
[00:55:58.900]and he just stated, in sort of the optimistic way,
[00:56:02.370]he stated two weeks ago, nationally,
[00:56:06.120]we removed 10 streams and rivers
[00:56:08.560]off of the impaired waterways listing.
[00:56:13.060]But he failed to mention Iowa alone
[00:56:15.560]has over 1000 streams and river reaches
[00:56:18.820]that are impaired, so at a national scale,
[00:56:21.290]to remove 10, it's good to think about
[00:56:24.460]the progress that's being made,
[00:56:25.910]but it's also important to think about
[00:56:27.300]what is the proportion of that progress.
[00:56:30.830]So it's quite small, relative,
[00:56:34.080]so I think that's what we start,
[00:56:36.172]we really need some really creative solutions
[00:56:38.340]to attack this in different angles and novel ways I think.
[00:56:47.377](muffled woman's voice speaking)
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