Spring brings more fears for #MissouriRiver flooding — The Kirksville Daily Express

2019 Nebraska flooding. Photo Credit: University of Nebraska Lincoln Crop Watch

From The Kirksville Daily Express (Mike Genet):

A year after flooding battered the Missouri River’s levee system, inundating towns and farmland and causing multiple closures to the nation’s interstate highway system, early forecasts warn that more of the same could be on the way: above-normal rainfall, greater than normal spring runoff. A USA TODAY Network analysis delves into records of an aging system of nearly a thousand levees where nobody knows how many were damaged last year or how many were repaired…

The forecast is a veritable index of meteorological plagues: above-normal rainfall; greater than normal spring runoff; thoroughly saturated soils; and an aging system of nearly a thousand levees where nobody knows how many were damaged last year and in previous floods or how many were repaired.

The 855 levee systems throughout the Missouri River basin protect at least half a million people and more than $92 billion in property. Yet a USA TODAY Network analysis of Army Corps of Engineers’ records found at least 144 levee systems haven’t been fully repaired and that only 231 show an inspection date.

Of those, nearly half were rated “unacceptable,” which means something could prevent the levee from performing as intended or a serious deficiency was not corrected. Only 3.5% were deemed acceptable; the rest were found to be “minimally acceptable.”

U.S. levee systems map via the U.S. Army Corps of Engineers. Click on the map to go to the interactive website.

Only 231 of the levee systems show any inspection date. For 38, the most recent inspection date was more than five years ago.

In the Army Corps’ Kansas City district, for example, about 70 projects, spanning 119 levees that requested repair assistance, are eligible for funding, but that doesn’t mean they’ll be ready if the waters rise like they did last year.

“Some of them have been repaired, but from a total system perspective, I don’t think any of them are whole,” said Jud Kneuvean, the district’s chief of emergency management, who expects full levee rehabilitation and repair to take at least another year.

In the meantime, the extent and impacts of flooding will depend on when and where the rain falls…

The 2,300-mile Missouri River begins in southwestern Montana, where the Gallatin, Madison and Jefferson rivers converge near the community of Three Forks, before gathering water from 10 states and parts of two Canadian provinces to become the “Big Muddy,” North America’s longest river.

In recent years, more rainfall has been pouring into the Missouri River basin, raising questions about whether climate change is bringing worsening floods more often. Data from the National Oceanic and Atmospheric Administration dating back to 1895 shows record-setting rainfalls in the area occurring more often. Last year, for example, was the wettest on record in North Dakota, South Dakota and Minnesota.

All that water adds to the challenge faced by Corps policymakers, who juggle sometimes conflicting priorities that include maintaining navigation; managing the reservoir system to prevent flooding; providing farmers with irrigation and hydropower; protecting endangered species; and preserving recreational opportunities.

While the priority is protecting human life and safety, the Corps’ decision-making sometimes puts special interest groups at odds, and the agency remains embroiled in controversy over whether the engineering of the river exacerbates flooding.

Things came to a head last year when a bomb cyclone in March melted all the snow in Nebraska and Iowa at once and dumped tremendous rain, swelling not just the Missouri, but the Elkhorn, Platte, James and Big Sioux rivers.

The Niobrara River in Nebraska breached the Spencer Dam on March 14, sending a wall of water downstream and into the Gavins Point reservoir near Yankton, South Dakota. At the peak, water flowed into the reservoir at 180,000 cubic feet per second — nine times more than the normal average for March. Meanwhile water was coursing into the rivers downstream of the dam and the effects of all that water were felt in nearly every community downstream.

Two other big rain events occurred in May and September. When the Corps’ Kansas City district deactivated its emergency operations center in December, it had been open for 279 days, the longest period on record…

Construction of the higher levee is in the administrative and planning stages, with actual construction activity set for fall.

Most of the Missouri’s levees fall into one of two categories: either federally built and locally operated or locally built and operated. The Corps inspects — and helps pay to repair — only the levees maintained to federal standards that participate in the federal flood program.

That exception means no one has a full list of damaged levees still in need of repair.

The number of levees that aren’t regularly inspected doesn’t surprise Neal Grigg, an engineering professor at Colorado State University who chaired a Corps-appointed review panel after 2011 flooding.

In an ideal management system, every levee “would be under the responsibility of some authority that was responsible and had enough money and good management capability to do that,” Grigg said.

But that’s not realistic, he added, noting that the Corps has tried through a task force to get some organization to the levee systems along the river, but it’s problematic, in part, because there are so many conflicting interests.

A host of agencies are cooperating to repair levees, but the progress is slow, said Missouri farmer Morris Heitman, who serves on the Missouri River Flood Task Force Levee Repair Working Group.

In addition to the Corps, the Federal Emergency Management Agency, the state of Missouri, the USDA Natural Resources Conservation Service and a large number of local levee districts all work to repair levees.

“We’re trying to dance with different agencies,” Heitman told the University of Missouri Extension. “All these agencies have their own requirements and parameters, and we’re trying to coordinate those to build a secure system against the river.”

Fixes to the 144 levee systems listed in disrepair in the Corps’ Omaha and Kansas City districts are in various stages of completion, and some aren’t expected to be done for more than a year.

In the Omaha district that includes Nebraska and Iowa, “pretty much all of the levees were damaged in one way or another,” said the corps’ Matt Krajewski.

While almost all of the district’s levees that qualify for federal aid have been restored to pre-2019 flood heights, Krajewski said they don’t offer the same level of “risk reduction” because they need final touches such as sod cover and drainage structures to protect against erosion. The Corps hopes to complete those repairs this summer.

In the meantime, the Corps is working to prepare its flood storage capacity by releasing more water than normal from its dams.

“We’re being really aggressive with our releases and trying to maintain our full flood storage,” said Eileen Williamson, a Corps spokeswoman for the Northwestern region.

But the projections for spring runoff don’t look good and may limit how much the Corps can do.

In February, the runoff was twice the normal average, said Kevin Grode, with the Corps’ Missouri River Basin Water Management district.

The James River, a tributary that flows out of South Dakota, has experienced flooding since March 13 last year and that flooding is forecast to continue. Moderate flooding is expected along the Big and Little Sioux Rivers in South Dakota and Iowa, and possibly in Montana’s Milk River basin. A risk of minor to moderate flooding is forecast from Nebraska City to the river’s confluence with the Mississippi in St. Louis.

But it’s not just the spring runoff that’s a problem, Grode said. The forecast also calls for “above average runoff for every month in 2020.”

John Remus, chief of the Corps’ Missouri River Water Management Division, said during a March briefing that if those projections are realized, “the 2020 runoff will be the ninth highest runoff in 122 years of record keeping.”

In March, a three-man team with Montana’s Helena-Lewis and Clark National Forest set off on horseback for a 35-mile, five-day journey into the wild North Fork of the Sun River, a tributary of the Missouri River.

They rode horses for the first 12 miles. When they reached a foot of snow, they switched to skis and took turns breaking trail.

Greeted by a half inch of new snow each morning, higher and higher they skied, encountering snow depths of 19 inches, then 2 feet, 9 inches and finally, 3 feet, 3 inches.

Karl Wetlaufer (NRCS), explaining the use of a Federal Snow Sampler, SnowEx, February 17, 2017.

At each elevation, aluminum tubes with non-stick coating were stuck into the snow to collect core samples used to measure the depth and water content of the snowpack.

“The numbers are used for everything from dam control along the Missouri River to regulating the locks on the barges of the Mississippi,” said Ian Bardwell, the forest’s wilderness and trails manager, who led the snow survey expedition. “It just depends on what level you are looking at it from.”

As of Wednesday, mountain snowpack in the Missouri River basin in Montana was 112% of normal, said Lucas Zukiewicz, a water supply specialist with the Department of Agriculture’s Natural Resources Conservation Service in Montana.

In 2018, Montana’s April snowpack was 150% of normal, then 7 to 9 inches of rain over six days drenched the Rocky Mountain Front, inundating communities in its shadow. The Corps was forced to release water from the Fort Peck Dam spillway, a rarity, as a result of surging flows. Had that same thing happened last year, flooding in states downstream would have been even worse.

“With the way things are changing with our climate,” said Arin Peters, a senior hydrologist for the National Weather Service in Great Falls, Montana, “it’s probably a matter of time before something combines to create a big catastrophe downstream.”

Yet for this year, there may be some good news downstream from the Montana snowpack, at the Gavins Point Dam in Yankton.

Gavins Point is what’s known as a reregulation dam, its purpose to even the Missouri’s flow from the reservoirs upstream. Because Gavins Point wasn’t designed to hold floodwater, its gates had to be opened last year, sending a surge downstream after Nebraska and parts of South Dakota were hit with rain and the bomb cyclone.

In November and December, Gavins Point was still releasing water at a rate of 80,000 cubic feet per second — more than five times the average flow, and something that had never happened before, said Tom Curran, the dam’s project manager.

The good news? Releasing all that water through the winter left the mainstem dam system drained to its multipurpose zone, where it has capacity to absorb runoff while also fulfilling its other functions, including recreation and downstream barge traffic.

Created by Imgur user Fejetlenfej , a geographer and GIS analyst with a ‘lifelong passion for beautiful maps,’ it highlights the massive expanse of river basins across the country – in particular, those which feed the Mississippi River, in pink.

2020 #OgallalaAquifer Summit will take place March 31-April 1, 2020 in Amarillo, Texas

Here’s the release from Colorado State University (Jennifer Dimas):

The 2020 Ogallala Aquifer Summit will take place in Amarillo, Texas, from March 31 to April 1, bringing together water management leaders from all eight Ogallala region states: Colorado, Kansas, New Mexico, Nebraska, Oklahoma, Texas, South Dakota and Wyoming. The dynamic, interactive event will focus on encouraging exchange among participants about innovative programs and effective approaches to addressing the region’s significant water-related challenges.

“Tackling Tough Question” is the theme of the event. Workshops and speakers will share and compare responses to questions such as: “What is the value of groundwater to current and future generations?” and “How do locally led actions aimed at addressing water challenges have larger-scale impact?”

“The summit provides a unique opportunity to strengthen collaborations among a diverse range of water-focused stakeholders,” said summit co-chair Meagan Schipanski, an associate professor in the Department of Soil and Crop Sciences at CSU. “Exploring where we have common vision and identifying innovative concepts or practices already being implemented can catalyze additional actions with potential to benefit the aquifer and Ogallala region communities over the short and long term.”

Schipanski co-directs the Ogallala Water Coordinated Agriculture Project (CAP) with Colorado Water Center director and summit co-chair Reagan Waskom, who is also a faculty member in Soil and Crop Sciences. The Ogallala Water CAP, supported by the U.S. Department of Agriculture’s National Institute of Food and Agriculture, has a multi-disciplinary team of 70 people based at 10 institutions in six Ogallala-region states. They are all engaged in collaborative research and outreach for sustaining agriculture and ecosystems in the region.

Some Ogallala Water CAP research and outreach results will be shared at the 2020 Ogallala Summit. The Ogallala Water CAP has led the coordination of the event, in partnership with colleagues at Texas A&M AgriLife, the Kansas Water Office, and the USDA-Agricultural Research Service-funded Ogallala Aquifer Program, with additional support provided by many individuals and organizations from the eight Ogallala states.

The 2020 Summit will highlight several activities and outcomes inspired by or expanded as a result of the 2018 Ogallala Summit. Participants will include producers; irrigation company and commodity group representatives; students and academics; local and state policy makers; groundwater management district leaders; crop consultants; agricultural lenders; state and federal agency staff; and others, including new and returning summit participants.

“Water conservation technologies are helpful, and we need more of them, but human decision-making is the real key to conserving the Ogallala,” said Brent Auvermann, center director at Texas A&M AgriLife Research – Amarillo. “The emergence of voluntary associations among agricultural water users to reduce groundwater use is an encouraging step, and we need to learn from those associations’ experiences with regard to what works, and what doesn’t, and what possibilities exist that don’t require expanding the regulatory state.”

The summit will take place over two half-days, starting at 11 a.m. Central Time (10 a.m. MDT) on Tuesday, March 31 and concluding the next day on Wednesday, April 1 at 2:30 p.m. The event includes a casual evening social on the evening of March 31 that will feature screening of a portion of the film “Rising Water,” by Nebraska filmmaker Becky McMillen, followed by a panel discussion on effective agricultural water-related communications.

Visit the 2020 Ogallala summit webpage to see a detailed agenda, lodging info, and to access online registration. Pre-registration is required, and space is limited. The registration deadline is Saturday, March 21 at midnight Central Time (11 p.m. MDT).

This event is open to credentialed members of the media. Please RSVP to Katie.ingels@kwo.ks.gov or amy.kremen@colostate.edu

The Ogallala aquifer, also referred to as the High Plains aquifer. Source: National Oceanic and Atmospheric Adminstration

2020 #OgallalaAquifer Summit in Amarillo, #TX, March 31 – April 1, 2020 — The #Kansas #Water Office

Here’s the release from the Kansas Water Office (Katie Patterson-Ingels, Amy Kremen):

8-State Conversation to Highlight Actions & Programs Benefitting the Aquifer, Ag, and Ogallala communities

The 2020 Ogallala Aquifer Summit will take place in Amarillo, Texas, from March 31 to April 1, bringing together water management leaders from all eight Ogallala region states: Colorado, Kansas, New Mexico, Nebraska, Oklahoma, Texas, South Dakota and Wyoming. The dynamic, interactive event will focus on encouraging exchange among participants about innovative programs and effective approaches being implemented to address the region’s significant water-related challenges.

“Tackling Tough Questions,” is the theme of the event. Workshops and speakers share and compare responses to questions such as: “What is the value of groundwater to current and future generations” and “how do locally-led actions aimed at addressing water challenges have larger-scale impact?”

“The summit provides a unique opportunity to strengthen collaborations among a diverse range of water-focused stakeholders,” said summit co-chair Meagan Schipanski, an associate professor in the Department of Soil and Crop Sciences at CSU. “Exploring where we have common vision and identifying innovative concepts or practices already being implemented can catalyze additional actions with potential to benefit the aquifer and Ogallala region communities over the short- and long-term.”

Schipanski co-directs the Ogallala Water Coordinated Agriculture Project (CAP) with Colorado Water Center director and summit co-chair Reagan Waskom, who is also a faculty member in Soil and Crop Sciences. The Ogallala Water CAP, supported by the U.S. Department of Agriculture’s National Institute of Food and Agriculture, has a multi-disciplinary team of 70 people based at 10 institutions in 6 Ogallala-region states, engaged in collaborative research and outreach aimed at sustaining agriculture and ecosystems in the region.

Some Ogallala Water CAP research and outreach results will be shared at the 2020 Ogallala Summit. The Ogallala Water CAP has led the coordination of this event, in partnership with colleagues at Texas A&M AgriLife, the Kansas Water Office, and the USDA-Agricultural Research Service-funded Ogallala Aquifer Program, with additional support provided by many other individuals and organizations from the eight Ogallala states.

The 2020 Summit will highlight several activities and outcomes inspired by or expanded as a result of the 2018 Ogallala Summit. Participants will include producers, irrigation company and commodity group representatives, students and academics, local and state policy makers, groundwater management district leaders, crop consultants, agricultural lenders, state and federal agency staff, and others, including new and returning summit participants.

“Water conservation technologies are helpful, and we need more of them, but human decision-making is the real key to conserving the Ogallala,” said Brent Auvermann, Center Director at Texas A&M AgriLife Research – Amarillo. “The emergence of voluntary associations among agricultural water users to reduce ground water use is an encouraging step, and we need to learn from those associations’ experiences with regard to what works, and what doesn’t, and what possibilities exist that don’t require expanding the regulatory state.”

The summit will take place over two half-days, starting at 11:00 a.m. Central Time on Tuesday, March 31 and concluding the next day on Wednesday, April 1 at 2:30 p.m. The event includes a casual evening social on the evening of March 31 that will feature screening of a portion of the film “Rising Water,” by Nebraska filmmaker Becky McMillen, followed by a panel discussion on effective agricultural water-related communications.

Visit the 2020 Ogallala summit webpage to see a detailed agenda, lodging info, and to access online registration. Pre-registration is required, and space is limited. The registration deadline is Saturday, March 21 at midnight Central Time.

This event is open to credentialed members of the media. Please RSVP to Katie.ingels@kwo.ks.gov or amy.kremen@colostate.edu.

Ogallala Aquifer. This map shows changes in Ogallala water levels from the period before the aquifer was tapped to 2015. Declining levels appear in red and orange, and rising levels appear in shades of blue. The darker the color, the greater the change. Gray indicates no significant change. Although water levels have actually risen in some areas, especially Nebraska, water levels are mostly in decline, namely from Kansas southward. Image credit: National Climate Assessment 2018

Study Details Effectiveness of Kansas Program That Pays Farmers to Conserve Water — @UnivOfKansas

Plots of land in Finney County, Kansas, utilize irrigation water from the High Plains Aquifer. Credit: NASA via the University of Kansas

From the University of Kansas (Jon Niccum):

Crops need water. And in the central United States, the increasing scarcity of water resources is becoming a threat to the nation’s food production.

Tsvetan Tsvetanov, assistant professor of economics at the University of Kansas, has analyzed a pilot program intended to conserve water in the agriculture-dependent region. His article “The Effectiveness of a Water Right Retirement Program at Conserving Water,” co-written with fellow KU economics professor Dietrich Earnhart, is published in the current issue of Land Economics.

“Residential water use is mostly problematic in California, and not so much here in Kansas. However, people don’t realize that residential use is tiny compared to agricultural use,” Tsvetanov said.

“I don’t want to discourage efforts to conserve water use among residential households. But if we want to really make a difference, it’s the agricultural sector that needs to change its practices.”

That’s the impetus behind the Kansas Water Right Transition Assistance Program (WTAP).

“If you’re a farmer, you need water to irrigate. If you don’t irrigate, you don’t get to sell your crops, and you lose money. So the state says if you reduce the amount of water you use, it’s actually going to pay you. So it’s essentially compensating you to irrigate less,” he said.

But this is not a day-to-day solution. The state recompenses farmers to permanently retire their water rights. The five-year pilot program that began in 2008 offers up to $2,000 for every acre-foot retired.

This benefits the High Plains Aquifer, the world’s largest freshwater aquifer system, which is located beneath much of the Great Plains. Around 21 million acre-feet of water is withdrawn from this system, primarily for agricultural purposes.

Tsvetanov and Earnhart’s work distinguishes the effectiveness between two target areas: creek sub-basins and high-priority areas. Their study (which is the first to directly estimate the effects of water right retirement) found WTAP resulted in no reduction of usage in the creek areas but substantial reduction in the high-priority areas.

“Our first thought was, ‘That’s not what we expected,’” Tsvetanov said.

“The creeks are the geographic majority of what’s being covered by the policy. The high-priority areas are called that for a reason — they’ve been struggling for many years. Our best guess is that farmers there were more primed to respond to the policy because there is awareness things are not looking good, and something needs to be done. So as soon as a policy became available which compensated them for the reduction of water use, they were quicker to take advantage of it.”

Of the eight states sitting atop the High Plains Aquifer, Texas is the worst in terms of water depletion volume. However, Kansas suffers from the fastest rate of depletion during the past half-century.

“Things are quite dire,” Tsvetanov said. “The western part of Kansas is more arid, so they don’t get as much precipitation as we do here in the east. Something needs to change in the long run, and this is just the first step.”

Tsvetanov initially was studying solar adoption while doing his postdoctoral work at Yale University in Connecticut. When visiting KU for a job interview, he assumed the sunny quality of the Wheat State would be a great fit for his research. He soon realized that few policies incentivized the adoption of solar.

“At that point, I thought, ‘I can’t really adapt solar research to the state of Kansas because there’s not much going on here.’ And then I started getting more interested in water scarcity because this truly is a big local issue,” he said.

A native of Bulgaria who was raised in India (as a member of a diplomat’s family), Tsvetanov is now in his fifth year at KU. He studies energy and environmental economics, specifically how individual household choices factor into energy efficiency and renewable resources.

The state of Kansas spent $2.9 million in the half decade that the WTAP pilot program ran. Roughly 6,000 acre-feet of water rights were permanently retired.

“Maybe it’s a start, but it’s not something you would expect to stabilize the depletion,” Tsvetanov said. “This is just a drop in the bucket. Essentially what we need is some alternative source of income for those people living out there, aside from irrigation-intensive agriculture.”

@USFWS to start releases from Lake McConaughy on February 17, 2020 for the Platte River Recovery Implementation Program

Platte River Recomery Implemtation Program area map.

From The Kearney Hub:

The U.S. Fish and Wildlife Service, in coordination with the Platte River Recovery Implementation Program, plans to release water from Lake McConaughy to benefit downstream habitat used by threatened and endangered species.

Releases will start Monday and may continue through March 15…

USFWS, PRRIP and Central Nebraska Public Power and Irrigation District staff will coordinate the releases, monitor weather and runoff conditions, and be prepared to scale back or end releases if required to minimize the risk of exceeding flood stage.

Current expectations include:

Environmental account water traveling down the North Platte channel below Lake McConaughy will be increased by approximately 300 cubic feet per second to 700 cfs.

– The river will remain well below the designated flood stage of 6 feet at the city of North Platte.

– Flows downstream of North Platte are expected to be significantly below flood stage.

– Flows at Grand Island should be approximately 700 cfs, or less than 6 inches higher than current flows.

– In the Overton to Grand Island stretch, the river stage is expected to be less than 1 foot above normal levels for this time of year.

Report: #Groundwater Availability of the Northern #HighPlainsAquifer in #Colorado, #Kansas, #Nebraska, #SouthDakota, and #Wyoming — @USGS #OgallalaAquifer

Click here to download the paper. Here’s the executive summary:

The Northern High Plains aquifer underlies about 93,000 square miles of Colorado, Kansas, Nebraska, South Dakota, and Wyoming and is the largest subregion of the nationally important High Plains aquifer. Irrigation, primarily using groundwater, has supported agricultural production since before 1940, resulting in nearly $50 billion in sales in 2012. In 2010, the High Plains aquifer had the largest groundwater withdrawals of any major aquifer system in the United States. Nearly one-half of those withdrawals were from the Northern High Plains aquifer, which has little hydrologic interaction with parts of the aquifer farther south. Land-surface elevation ranges from more than 7,400 feet (ft) near the western edge to less than 1,100 ft near the eastern edge. Major stream primarily flow west to east and include the Big Blue River, Elkhorn River, Loup River, Niobrara River, Republican River and Platte River with its two forks—the North Platte River and South Platte River. Population in the Northern High Plain aquifer area is sparse with only 2 cities having a population greater than 30,000.

Droughts across much of the area from 2001 to 2007, combined with recent (2004–18) legislation, have heightened concerns regarding future groundwater availability and highlighted the need for science-based water-resource management. Groundwater models with the capability to provide forecasts of groundwater availability and related stream base flows from the Northern High Plains aquifer were published recently (2016) and were used to analyze groundwater availability. Stream base flows are generally the dominant component of total streamflow in the Northern High Plains aquifer, and total streamflows or shortages thereof define conjunctive management triggers, at least in Nebraska. Groundwater availability was evaluated through comparison of aquifer-scale water budgets compared for periods before and after major groundwater development and across selected future forecasts. Groundwater-level declines and the forecast amount of groundwater in storage in the aquifer also were examined.

Major Findings

  • Aquifer losses to irrigation withdrawals increased greatly from 1940 to 2009 and were the largest average 2000–9 outflow (49 percent of total).
  • Basin to basin groundwater flows were not a large part of basin water budgets.
  • Development of irrigated land and associated withdrawals were not uniform across the Northern High Plains aquifer, and different parts of the Northern High Plains aquifer responded differently to agricultural development.
  • For the Northern High Plains aquifer, areas with high recharge and low evapotranspiration had the most streamflow, and most streams only remove water from the aquifer.
  • Results of a baseline future forecast indicated that groundwater levels declined overall, indicating an overdraft of the aquifer when climate was about average and agricultural development was held at the same state as 2009.
  • Results of two human stresses future forecasts indicated that increases of 13 percent or 23 percent in agricultural development, mostly near areas of previous development, caused increases in groundwater pumping of 8 percent or 11 percent, and resulted in continued groundwater-level declines, at rates 0.3 or 0.5 million acre-feet per year larger than the baseline forecast.
  • Results of environmental stresses forecasts (generated from two downscalings of global climate model outputs) compared with the baseline forecast indicated that even though annual precipitation was nearly the same, differences in temperature and a redistribution of precipitation from the spring to the growing season (from about May 1 through September 30), created a large (12–15 percent) decrease in recharge to the aquifer.
  • For the two environmental stresses forecasts, temperature and precipitation were distributed about the same among basins of the Northern High Plains aquifer, but the amounts were different.
  • Citation

    Peterson, S.M., Traylor, J.P., and Guira, M., 2020, Groundwater availability of the Northern High Plains aquifer in Colorado, Kansas, Nebraska, South Dakota, and Wyoming: U.S. Geological Survey Professional Paper 1864, 57 p., https://doi.org/10.3133/pp1864.

    Small streams and wetlands are key parts of river networks – here’s why they need protection — The Conversation


    Biscuit Brook, a popular fly fishing spot in New York’s Catskill Mountains.
    Ellen Wohl, CC BY-ND

    Ellen Wohl, Colorado State University

    The Trump administration is proposing to redefine a key term in the Clean Water Act: “Waters of the United States.” This deceptively simple phrase describes which streams, lakes, wetlands and other water bodies qualify for federal protection under the law.

    Government regulators, landowners, conservationists and other groups have struggled to agree on what it means for more than 30 years. Those who support a broad definition believe the federal government has a broad role in protecting waters – even if they are small, isolated, or present only during wet seasons. Others say that approach infringes on private property rights, and want to limit which waters count.

    I study rivers, and served on a committee that reviewed the science supporting the Obama administration’s 2015 Clean Water Rule. This measure, which defined waters of the United States broadly, is what the Trump administration wants to rewrite.

    The Trump proposal goes completely against scientists’ understanding of how rivers work. In my view, the proposed changes will strip rivers of their ability to provide water clean enough to support life, and will enhance the spiral of increasingly damaging floods that is already occurring nationwide. To understand why, it’s worth looking closely at how connected smaller bodies of waters act as both buffers and filters for larger rivers and streams.

    Ephemeral channels like upper Antelope Creek in Arizona flow only after rain or snowfall, but are important parts of larger river systems.
    Ellen Wohl, CC BY-ND

    Parts of a whole

    The fact that something is unseen does not make it unimportant. Think of your own circulatory system. You can see some veins in your hands and arms, and feel the pulse in your carotid artery with your finger. But you can’t see the capillaries – tiny channels that support vital processes. Nutrients, oxygen and carbon dioxide move between your blood and the fluids surrounding the cells of your body, passing through the capillaries.

    And just because something is abundant does not reduce each single unit’s value. For example, when we look at a tree we tend to see a mass of leaves. The tree won’t suffer much if some leaves are damaged, especially if they can regrow. But if it loses all of its leaves, the tree will likely die.

    These systems resemble maps of river networks, like the small tributary rivers that feed into great rivers such as the Mississippi or the Columbia. Capillaries feed small veins that flow into larger veins in the human body, and leaves feed twigs that sprout from larger branches and the trunk.

    A conservation biologist explains how the wetlands and backwaters of Oregon’s Willamette River system were critical to rescuing the Oregon chub, one of this valley’s most endangered fishes, from near extinction.

    Microbes at work

    Comparing these analogs to rivers also is apt in another way. A river is an ecosystem, and some of its most important components can’t be seen.

    Small channels in a river network are points of entry for most of the materials that move through it, and also sites where potentially harmful materials can be biologically processed. The unseen portions of a river below the streambed function like a human’s liver by filtering out these harmful materials. In fact, this metaphor applies to headwater streams in general. Without the liver, toxins would accumulate until the organism dies.

    As an illustration, consider how rivers process nutrients such as nitrogen and phosphorus, which are essential for plant and animal life but also have become widespread pollutants. Fossil fuel combustion and agricultural fertilizers have increased the amount of nitrogen and phosphorus circulating in air, water and soil. When they accumulate in rivers, lakes and bays, excess nutrients can cause algal blooms that deplete oxygen from the water, killing fish and other aquatic animals and creating “dead zones.” Excess nitrogen in drinking water is also a serious human health threat.

    River ecosystems are full of microbes in unseen places, such as under the roots of trees growing along the channel; in sediments immediately beneath the streambed; and in the mucky ooze of silt, clay, and decomposing leaves trapped upstream from logs in the channel. Microbes can efficiently remove nutrients from water, taking them up in their tissues and in turn serving as food for insects, and then fish, birds, otters and so on. They are found mainly in and around smaller channels that make up an estimated 70 to 80 percent of the total length of any river network.

    Map of the Missouri River basin showing its network of tributaries.
    Missouri River Water Trail, CC BY-ND

    Water does not necessarily move very efficiently through these small channels. It may pond temporarily above a small logjam, or linger in an eddy. Where a large boulder obstructs the stream flow, some of the water is forced down into the streambed, where it moves slowly through sediments before welling back up into the channel. But that’s good. Microbes thrive in these slower zones, and where the movement of dissolved nutrients slows for even a matter of minutes, they can remove nutrients from the water.

    Flood control and habitat

    Other critical processes, such as flood control, take place in small upstream river channels. When rain concentrates in a river fed by numerous small streams, and surrounded by bottomland forests and floodplain wetlands, it moves more slowly across the landscape than if it were running off over land. This process reduces flood peaks and allows more water to percolate down into the ground. Disconnect the small streams from their floodplains, or pave and plow the small channels, and rain will move quickly from uplands into the larger channels, causing damaging floods.

    These networks also provide critical habitat for many species. Streams that are dry much of the year, and wetlands with no surface flow into or out of them, are just as important to the health of a river network as streams that flow year-round.

    Marvelously adapted organisms in dry streams wait for periods when life-giving water flows in. When the water comes, these creatures burst into action, with microbes removing nitrate just as in perennially flowing streams. Amphibians move down from forests to temporarily flooded vernal wetlands to breed. Tiny fish, such as brassy minnows, have waited out the dry season in pools that hold water year-round. When flowing water connects the pools, the minnows speed through breeding and laying eggs that then grow into mature fish in a short period of time.

    The Arikaree River in eastern Colorado is an intermittent stream that supports brassy minnow, a species of concern in the state.
    Ellen Wohl, CC BY-NC

    Scientific sleuthing with chemical tracers has shown that wetlands with no visible surface connection to other water bodies are in fact connected via unseen subterranean pathways used by water and microbes. A river network is not simply a gutter. It is an ecosystem, and all the parts, unseen or seen, matter. I believe the current proposal to alter the Clean Water Act will fundamentally damage rivers’ ability to support all life – including us.The Conversation

    Ellen Wohl, Professor of Geosciences, Colorado State University

    This article is republished from The Conversation under a Creative Commons license. Read the original article.