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Stream Mitigation Permitting & Requirements Webinar

By preserving and restoring wetlands, habitats, and streams in designated regions, we can balance out unavoidable damages and provide no net loss to the environment. However, regulations and requirements often impede progress in this pursuit of balance. The science of stream mitigation is evolving rapidly as does the development of state and Corps policies governing stream assessment and compensation requirements.

Listen in as our environmental scientist Nichoel Church, PWS helps define a clear path to stream and wetland mitigation through their designated permits and requirements.

Webinar Agenda

  • Fundamentals of 404 Permitting & Mitigation Requirements (0:18)
  • Understanding the Clean Water Act (0:54)
  • Types of Wetlands & Streams Commonly Found in Iowa (1:38)
  • Defining Jurisdictional Waters (2:50)
  • Regulations That Require Permits (4:25)
  • Project Scheduling & Permitting (5:51)
  • Triggering the Need for a 404 Permit (7:21)
  • Calculating Impacts Through the Iowa Stream Mitigation Method (9:57)
  • Compensating for Loss of Jurisdictional Resources (11:36)
  • Permittee Responsible Mitigation (PRM) (12:08)
  • Elements of PRM (13:49)
  • Understanding the Benefits of Mitigation Banking (17:14)
  • Breakdown of Snyder & Associates Mitigation Banks (18:44)

Nichoel Church Head Shot

Nichoel Church, PWS

Environmental Scientist

Nichoel Church, PWS

Environmental Scientist

Mitigation banking development, Wetland delineation, Section 404 permitting, Endangered Species Act (Section 7 Consultation)

Fundamentals of 404 Permitting & Mitigation Requirements (0:18)

Hi, my name is Nichoel Church. I’m an environmental scientist with Snyder & Associates, and today I’m going to be talking about stream mitigation, fundamentals of 404 permitting, and mitigation requirements.

Snyder & Associates is a multidisciplinary civil engineering firm. Our repeat business focuses on government clients, and we serve several municipalities ranging from hundred thousand to 150,000 people. But we also have a large footprint within the private sector. We’ve been providing professional services for over 40 years, and I’ve had the pleasure of working with agencies all across the states where we have offices.

Understanding the Clean Water Act (0:54)

The Clean Water Act of 1972 celebrated 50 years in October. This act regulates the discharge of pollutants and navigable waters, outlines water quality standards, and promotes the no-net loss of wetlands into the “Waters of the United States.” A quote from the Clean Water Act is, “To restore and maintain the chemical, physical, and biological integrity of the nation’s waters. A permit is required if waters of the US will be polluted or destroyed, and we call that filled.”

Today I’m going to be focusing on Section 404 and Clean Water Act mitigation requirements. But before we get into that, we have to understand what is a wetland. A wetland is comprised of hydrophytic vegetation, hydric soils, and hydrology.

Types of Wetlands & Streams Commonly Found in Iowa (1:38)


A restored stream with protected sanitary sewer infrastructure and improved ecological functions and stream habitat diversity.

A restored stream with protected sanitary sewer infrastructure, improved ecological function, and stream habitat diversity.

Types of wetlands. In Iowa, our wetlands are classified by being emergent, scrub-shrub, or forested. Emergent is comprised of herbaceous vegetation, scrub-shrub wetlands are comprised of shrubs in the name, but they can also have herbaceous vegetation surrounding them, and then Forested wetlands are comprised of areas that are dominated by 50% or more canopy cover with trees that are 15 feet or taller.

Types of streams. There are Ephemeral, Intermittent, and Perennial streams. The Ephemerals flow only during and after rain events. Basically, they receive their rain either from tile or through runoff, and their water table is far below the stream bed, so they rely on that precipitation.

Intermittent, they flow during normal conditions, so during a wet season. But, they don’t have to flow year-round, and they are connected to groundwater, and then precipitation and runoff just provides that supplemental flow. And then our perennial streams have continuous flow in the stream beds during most years, basically every year, and the water table is located above the stream bed. So, their source of flow is groundwater, precipitation, and runoff.

Defining Jurisdictional Waters (2:50)

Now that we’ve talked about natural resources that are covered under permitting with Section 404 of the Clean Water Act, we’re going to talk about what is jurisdictional. Jurisdictional waters listed on the slide are under the regulation of the Clean Water Act, which is permitted by the US Army Corps of Engineers and enforced by the US EPA. And again, the Clean Water Act just prohibits the discharge of pollutants from point sources into “navigable waters,” which are referred to in the Clean Water Act as “Waters of the United States.”

So, the definition of “Waters of the United States,” therefore, really sets the boundaries for the Corps and EPAs authority, their jurisdiction. On this list of resources, you might notice that one of them isn’t listed that we just talked about, would be Ephemeral streams. In 2015, under the Obama administration, the Clean Water Rule was implemented, and the federal court ruled that this definition of ‘waters in the United States” was too expansive. And then, in 2020, under the Trump administration, the Navigable Waters Protection Rule came into play, and this new regulation completely removed ephemeral streams from being jurisdictional. So currently, under current guidance in 2022, ephemeral streams are not jurisdiction.

Moving forward onto non-jurisdictional waters. We’ve got a broad list. Again, just anything that is not considered a wetland by definition or does not have a defined bed and bank that could be determined to be a stream is likely not jurisdictional if it does not have direct connectivity to a jurisdictional feature.

Regulations That Require Permits (4:25)

So, we understand what natural resources are protected under the Clean Water Act, and we know which resources the Corps and EPA have jurisdiction over through the Clean Water Act. Now we’re going to move forward with regulations that require permits. So, the Clean Water Act talked about it already. We have Section 404, in which the Corps requires a permit for the discharge of dredger fill material into the “Waters of the United States,” and along with that Section 404 comes the state certification for water quality, which is under Section 401. In Iowa, the Iowa DNR processes the 401 certifications and submits that to the Corps for the permit.

Additionally, we have the Rivers and Harbors Act of 1899, which could require a Section 10 permit for activities that could affect navigable “Waters of the United States.” In Iowa, that is the Mississippi River, Iowa River, Des Moines River, and the Missouri River.

So, I’ve mostly talked about 404, Clean Water Act, and it requires permitting from the Corps for those impacts. In Iowa, we primarily work with the Rock Island District. As you can see from this map, they cover the majority of the state. However, we also work with the Omaha District, and I’ve never worked with the Kansas City District on a permanent in Iowa. Usually, the Corps in Rock Island or Omaha District will take jurisdiction, but technically their jurisdictional boundary comes into Southern Iowa.

Project Scheduling & Permitting (5:51)

Project scheduling is very important for consultants, landowners, and municipalities that are involved. You know, whoever the applicant for the permit will be to understand that it is required for wetland delineations to be completed within the entire project area. We cannot complete wetland delineations in an area where we think wetlands might be. For example, along a flood plain within included project area would be a farm field, and we can’t focus solely on the flood plain. We would have to look at everything, so the flood plain and the farm field, to document connectivity because there could be farm wetlands in that field, and they may have connectivity to that flood plain. And then drainage features as well. So, they may not be jurisdictional, but we want to identify where ditches are and any low-depressional features. And I already mentioned this, but flood plains as well. We should be looking at the area along the creeks. Just because we’re in a flood plain doesn’t mean it’s going to be a wetland, and just because we’re in a farm field doesn’t mean that you’re going to find wetlands either. Looking at the entire project area is very important so we can tell the Corps, here’s what we identified, and here are our baseline conditions moving forward with permitting.

Wetland delineations can only be completed during the growing season, which is typically from April through October. And wetland delineations are only good for five years. So, if a project timeline would take longer than that, the wetland delineation might have to be completed again with an addendum attached to the original wetland delineation report.

Triggering the Need for a 404 Permit (7:21)

What would trigger the need for a 404 permit? We work on these day in and day out. Any sort of construction activity that would cross a stream or a wetland that could include roads, bridges, trails development, and potentially residential, or commercial. And then the construction of any dams, dikes, weirs, or impoundment structures that would trigger a permit—replacing utilities or maintenance that might trigger a permit. Stream improvements or channelizing, a stream bank stabilization which would be the placement of rip rap along the channel. And then dredging if there is fill placement within that jurisdictional feature body of water and culvert replacement as well. So, these are just examples of typical activities that we see every day that requires permits.

Section 404 permitting does not always require mitigation. That’s very important to understand when we talk about permitting. That doesn’t mean that mitigation will be required. A permit may be required for a project, and it might have mitigation, or it might not. What would trigger mitigation requirements are a tenth of an acre of wetland impact or 0.03 acres of the stream. Permits are different, and they’re quantified based on impacts as well. But for a nationwide permit, it has to be less than a half-acre of impact. Once you’re over that half-acre threshold, it bumps up to an individual permit which takes a lot longer, and there’s a lot of supplemental documentation required for that. And then streams for permitting used to be 300 linear feet, and that is still typical for most Nationwide, but there are a couple of Nationwide and regional permits now that have a larger footprint for streams ranging from 500 to 1500 linear feet.

So, we’ve talked about natural resources and what may or may not be jurisdictional as well as permitting. And along with permitting proposed development, and roadway, it doesn’t matter what it is, the Corps and the DNR want to know how is your project avoiding wetlands. Can the impacts on those wetlands be avoided or minimized? If they can be avoided, that’s the route that they want you to take. If they can be minimized, the impacts on those jurisdictional features could be less in any way than they want to talk to you about it. And they also want to talk about options that you have considered and why they were dismissed. And then, if those impacts cannot be avoided or minimized, that’s when mitigation could be triggered, and that could be either through permitting responsible or through the purchase of mitigation credits, which we’ll talk about in just a little bit.

Calculating Impacts Through the Iowa Stream Mitigation Method (9:57)

So, the Iowa Stream mitigation method is used to calculate impacts for permits. It’s also used to develop mitigation banks, so it’s got an impact calculator, and then it’s got an extreme benefit calculator. This is used pretty widely throughout our state now, and it’s been really helpful in providing consistency across the Corps for stream impacts as well as establishing mitigation banks. On the impact side of things, we talked about that 0.03-acre threshold for streams. That is new as in that was established in the spring of 2022. That used to be 300 linear feet before that, and the Corps headquarters in DC just decided, “you know what, some districts were using the 300-foot rule, and some weren’t. Some had their guidelines on what they would use for mitigation. We’re just going to make it a standard 0.03 acres threshold for streams across the board.” So now, rather than just saying linear feet of stream, you have to calculate the length of the channel as well as the width that you are impacted.

And then in that credit calculator, I should mention it also takes into account the type of channel it is. So, stream mitigation, when it is calculated through the calculator, it calculates it in credits. So intermittent streams have a lower ratio compared to perennial streams because perennial streams are larger systems. They might have a higher impact. As well as the impact activity. Are you installing and replacing a culvert or expanding a culvert? Or is it something where it’s going to be a complete loss of channel for you filling in the channel or channelizing it, straightening the stream? So, each impact activity listed in the calculator has a certain ratio, and that is how credits are determined. Oh, and length. Length is also considered.

Compensating for Loss of Jurisdictional Resources (11:36)

What is compensatory mitigation? We’ve talked about mitigation already, and it is the compensation for the loss of that jurisdictional resource. Your project has to impact 0.11 acres of wetland. Your obligation through your 404 permits for no net loss is to offset the loss of the impacted wetland either through the purchase of mitigation bank credit, which is option number one. If mitigation bank credits are not available in your service area, then your project can move forward with permitting responsible mitigation.

Permittee Responsible Mitigation (PRM) (12:08)

I’d like to talk about permitting responsible mitigation first, even though it’s the second option that the 2008 mitigation rule designates as preferred. There may not be credits available within a service area. So PRM would be required. And also, before the mitigation bank calculator was developed and we had stream mitigation banks, this is how we completed projects.

In this example I have on the screen right now, this is a permit-responsible mitigation project, and this is our project location: Sugar Creek in West Des Moines. You can see the bottom photo is what it looked like in 2015, and the top photo is what it looked like in 2018 post-construction. Again, that’s just our project, and we were impacting a meander along the stream because it was eroded and needed to be stabilized for a new bridge crossing. There weren’t mitigation banks that offered stream credit, so we moved forward with permit-responsible mitigation, which was completed along Jordan Creek at Brookview Middle School in Waukee. And what we did was we worked with the Corps and determined that we needed to remeander the stream a certain length. This channel was straightened, as you can see in the upper left photo. Banks were very eroded, definitely sized, and it was down-cutting. So, stabilizing the channel, as you can see in the upper right picture, was a success. It required monitoring and it required maintenance, and the city of West Des Moines had to work out a deal with the city of Waukee. Permittees responsible can be very expensive, especially if property acquisition is required, and they can also fail, and that is one of the reasons why the 2008 Mitigation Rule refers to the purchase of mitigation bank credit if available rather than PRM.

Elements of PRM (13:49)

Elements of PRM through stream mitigation. You’ve got planning and design construction, annual monitoring, and maintenance. With maintenance, you have specific requirements, such as less than 5% invasive species cover throughout the vegetation along the riparian buffer. In addition, if tree plantings were part of your mitigation plan, then they have a high percentage rate for survival, and if they die, you have to replace them and plant new trees. And again, eventually, Mother Nature will take over, and it has to be a natural system. And if your mitigation site fails, then you either have to find a new mitigation site for PRM, or you have to buy mitigation bank credit if available. So that additional risk component is there.

Purchasing Mitigation Credits (14:34)

The first option is to purchase credits from a stream mitigation bank within your service area. This is an easy, time-saving way to satisfy your mitigation requirements for your permit. You write a check and walk away. There’s no construction, there’s no mitigation plan, and there are no performance standards that require maintenance and monitoring. Developing a mitigation bank, on the other hand, is a lot easier for the agencies because mitigation banks are larger, and they improve a large area of natural resources rather than the pocket permittee-responsible mitigation plans that would be completed throughout our entire state. So, it reduces the number of mitigation plans coming into the agencies for review. They can focus on larger water quality improvement projects that benefit watersheds and service areas, and it’s an easy way to satisfy mitigation for the applicant. Here is a photo of the mitigation bank service areas in Iowa.

Developing A Stream Mitigation Bank (15:37)

To develop a stream mitigation bank, you have to go through about a 12 to 18-month approval process through what is called the IRT, which is the Interagency Review team, which consists of the US Army Corps of Engineers, the US EPA, Iowa DNR, Fish, and Wildlife Service, and NRCS is also a member. Through that approval process, you know to submit several types of documentation, which includes a prospectus, a mitigation bank instrument, and that includes conservation easement as well as moving forward with construction and as-built and monitoring. For the bank sponsors, there are no guarantees when they will sell credits. You know this isn’t a program that is compensated for within the first couple of years. Mitigation banks typically have a range of seven to 10 years and should be considered a long-term investment, but they are very beneficial if you have a natural resource that needs to be improved. For this example, this is our Niebuhr stream mitigation bank on the slide and Buck Creek, which is a south view, so the stream is flowing downstream, but that straight channel there is on your right and in the middle. Approximately 3000 linear feet of the stream were then remanded along its natural alignment and remanded to approximately 5,000 linear feet.

We also were able to create wetlands along the riparian buffer, which helped with flood storage capacity and water quality improvements for tile outlets along those ag fields. So, it’s a bonus.

Understanding the Benefits of Mitigation Banking (17:14)

Benefits of mitigation banking. The landowner, want their resource improved, but they also want to earn a profit, and that’s through the sale of credits, and the watershed wins too. I mean, it’s just kind of a win-win all around. Here are several photos from our mitigation banks that we monitor.

I know we’re focusing on streams, but I wanted to throw in a slide about wetland mitigation banking benefits because they’re also important, and they are a resource that is protected under the Clean Water Act. This photo is an aerial view, mid-construction of our C&W Hunter Mitigation Bank stream mitigation banking benefits photo here of our dam removal project at Hydroelectric Dam in Fort Dodge along the Des Moines River.

That is one example of a benefit. Dam removal improves water quality and restores fish passage, but not all stream mitigation banks remove dams, so stabilizing streams, reconnecting flood plains, adding floodplain benches to help with that reconnection of the floodplain, and daylighting tile outlets to help with water quality within the riparian buffer, remeandering straight channels and establishing a riparian buffer along areas that don’t have a buffer today. So, an example would be just a farm field, converting that to a riparian buffer to filter nutrients before that runoff hits the channel. And then we’d already talked about daylighting the tiles, but exposing those tile outlets within the riparian buffer and allowing the nutrients to flow through the buffer and then hit the channel rather than outing directly into the streams.

Breakdown of Snyder & Associates Mitigation Banks (18:44)

One of my first mitigation bank projects that I worked on was Black Hawk Mitigation Bank, so this one’s near and dear to my heart. It’s a photo of the entrance and then an aerial view of when it was flooded.

Aerial view of construction at Niebuhr Mitigation bank

Niebuhr Stream Mitigation Bank

Our Niebuhr Stream Mitigation Bank is in Breer County, so just north of Black Hawk County. I kind of already talked about this one a little bit, but it restored meanders along a new channel alignment for a straightened stream. And here are some photos of us monitoring this May.

The Des Moines River Mitigation Bank in Fort Dodge. This mitigation bank was established by removing two dams along the Des Moines River. The largest one was the Hydroelectric Dam, and it also included the removal of the Little Dam, which was a low-head dam. We also restored riparian buffer along the Des Moines River, and we also restored riparian buffer along the Little Dam at Sunkissed Meadows Park in Fort Dodge, which they love because it’s full of wildflowers and they have a disc golf park, and it’s a lot more interesting to play disc golf in that sort of setting rather than just having a mowed, manicured lawn surrounding everything. So, it makes it a little more interesting.

Our Bilar Stream Mitigation Bank is in Johnson County, and that also remanded a straighten channel. This is one of the smaller mitigation banks that we have, but a huge benefit to the watershed.

And our Pabst wetland and stream mitigation bank was constructed in the Spring of 2022. It’s in Hardin County, and that one had wetland and stream improvements that you can see here post-construction, had stabilization of stream banks. We installed a few ripples for grade control, and they also function as low-water crossings then, we established floodplain benches along the channel to reconnect it to its floodplain. And those are stream mitigation banks that we’ve worked on.

That concludes my presentation, and I hope that you guys learn something about 404 permitting and mitigation requirements. If you have any questions, feel free to reach out and email me or give us a call at Snyder (515) 964-2020 and let us know if we can help with permitting for your project or if you have any questions. Thank you.

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