What Texas engineers need to know about NWP 58 and WOTUS compliance

"Total nominal costs to implement recommended projects in this plan are $174 billion (2023 dollars), more than double the cost of the 2022 State Water Plan" reads the recently posted draft 2027 State Water Plan for Texas. While multiple reasons for this increase were cited, the draft mentions a broad trend: water supply infrastructure projects are becoming increasingly costly as regions pursue more distant and complex sources of supply.

As anthropogenic sprawl in Texas continues to mount, the demand for water will continue to grow, and critical water infrastructure will be needed. As Texas city planners, engineers and contractors rise to meet this challenge, they will inevitably find U.S. Army Corps of Engineers (USACE) permitting is a hurdle for timely project completion.

USACE is the federal entity that regulates jurisdictional Waters of the U.S. (WOTUS), so filling, dredging or placing temporary material inside these streams for the construction of utility lines must be covered under the conditions of Nationwide Permit 58 - Utility Line Activities for Water and Other Substances (NWP 58). NWP 58 has a list of conditions to conform to, though the conditions regarding mitigation, pre-construction notifications and losses to WOTUS are pertinent to focus on given they are part of nearly every permitted project's scope.

Mitigation and linear crossings

General Condition 23 receives the most attention from engineers due to its incredible potential to increase project cost. General Condition 23(c) states: "Compensatory mitigation at a minimum one-for-one ratio will be required for all wetland losses that exceed 1/10-acre and require pre-construction notification."

The most common — and likely simplest — way of mitigating at a one-to-one ratio for a project's impacts is purchasing mitigation credits through a mitigation bank. Credits issued through these banks are market driven and can easily see total prices of hundreds of thousands of dollars.

But water transmission lines can span miles. What's an engineer to do? Note 2 of NWP 58 may offer a sigh of relief: "For linear projects crossing a single or multiple waterbodies several times at separate and distant locations, each crossing is considered a single and complete project for purposes of NWP authorization."

This means that the amount of permanent losses to WOTUS (which jurisdictional wetlands are umbrellaed under) only tally up per crossing. A project can propose filling 0.08 of an acre of one wetland at one crossing and 0.06 acre of one wetland at another without exceeding their 1/10th of an acre threshold. This applies to streams and other WOTUS too.

However, engineers should be careful. If one crossing requires a pre-construction notification, that submitted notification will have to include the entirety of the project and disclose all losses of WOTUS at all other crossings (even though these other crossings, as single and complete projects, will still tally their loss per crossing).

See paragraph (b)(4) of General Condition 32: "For linear projects where one or more single and complete crossings require preconstruction notification, the PCN must include the quantity of anticipated losses of wetlands, other special aquatic sites, and other waters for each single and complete crossing of those wetlands, other special aquatic sites, and other waters (including those single and complete crossings authorized by an NWP but do not require PCNs)."

Returning to pre-construction contours

General Condition 23 (and the definition of "loss of waters of the United States") may ease some worry as well: "Waters of the United States temporarily filled, flooded, excavated, or drained, but restored to pre-construction contours and elevations after construction, are not included in the measurement of loss of waters of the United States." Jurisdictional WOTUS can be temporarily impacted and will not count towards the project's total WOTUS loss as long as those WOTUS are returned to pre-construction contours.

Thus, when an engineer receives a WOTUS delineation exhibit lit up with green and blue polygons indicating jurisdictional WOTUS are present within the proposed transmission alignment, they need not necessarily lose hope in the project or assume they are staring down the barrel of hefty mitigation costs. Note 2 and paragraph (b)(4) of General Condition 32 may offer the design phase some runway.

However, temporarily impacting forested and scrub/shrub wetlands warrants caution (even if returning to pre-construction contours). Temporarily impacting these wetlands may still count as formal loss to WOTUS because disturbing their vegetation may constitute "adverse effect." The vegetation of these classes of wetlands takes years to reach pre-construction conditions.

Streambeds

Jurisdictional streams are subject to a lower threshold for compensatory mitigation. General Condition 23(d) states: "Compensatory mitigation at a minimum one-for-one ratio will be required for all losses of stream bed that exceed 3/100-acre and require pre-construction notification."

Does this mean that any loss to jurisdictional streambeds exceeding 3/100s of an acre immediately triggers a PCN requirement and compensatory mitigation? Not necessarily. Compensatory mitigation is only required for streambed losses that exceed 3/100s of an acre and require a PCN. A project may propose more than a 3/100s of an acre streambed loss and yet not require a PCN or compensatory mitigation. As the permit reads, the kicker is the PCN requirement.

So what triggers a PCN?

When reviewing PCN triggers it's crucial to review the regional conditions for the district the project is located in as they are ecologically specific to the region. These regional conditions vary widely. For example, in the Fort Worth and Galveston districts, activities proposed within WOTUS that have "ecologically unique" and "sensitive" areas such as bald cypress swamps, water tupelo swamps and pitcher plant bogs require a PCN. Uniquely, the Galveston District prohibits using NWPs (saving NWP 3) to authorize activities in mangrove marshes, coastal swale dunes and Columbia bottomlands, which are ecologically unique areas to the district. And as of the recently published regional conditions for the Albuquerque District, all activities within waterbodies regulated by Section 404 of the Clean Water Act now require a PCN; granted the geographic range of this region within Texas is admittedly dry compared to the Fort Worth and Galveston districts.

Most engineers are familiar with the aforementioned 1/10 of an acre number as the hallmark PCN trigger as it is nearly universal. But solely concentrating design efforts here is myopic. A project can very well stay under 1/10th of an acre of jurisdictional wetland loss, exceed 3/100s of an acre of streambed loss and trip an inconspicuous General Condition within NWP 58, which then triggers a PCN and forces compensatory mitigation for that loss of streambed.

On top of mitigation costs, preparing a PCN requires the labor of GIS analysts, environmental scientists and the preparation of typical cross-sections where loss of WOTUS is proposed complete with cubic yards of fill calculations, proposed and existing grades, and more. Understanding the General Conditions (and regional conditions) and permit triggers is vital, and two in particular deserve attention due to their conspicuous nature and universality in the NWP program.

General Condition 20

General Condition 20 states: "Non-federal permittees must submit a pre-construction notification to the district engineer if the NWP activity might have the potential to cause effects to any historic properties listed on, determined to be eligible for listing on, or potentially eligible for listing on the National Register of Historic Places, including previously unidentified properties."

A desktop review conducted by a professional archaeologist can determine the project's potential to impact historic properties. While this General Condition trigger for a PCN is rare, it would be prudent for planners and engineers to be mindful of any historic structures observed on site. Note that the General Condition includes previously unidentified properties. With USACE permitting, the potential for a project's impact on historic places cannot be an afterthought. Useful sites to determine a project's risk to trigger this general condition are TxDOT's Historic Resources Aggregator and the Texas Historical Commission Atlas Map.

General Condition 18

General Condition 18 requires that non-federal permittees "must submit a pre-construction notification to the district engineer if any listed species (or species proposed for listing) or designated critical habitat (or habitat areas proposed as such) might be affected or is in the vicinity of the activity." If the project may affect any listed species, even species that are proposed for listing, a pre-construction notification must be submitted. This General Condition is manageable when a listed species has a small geographic range and is designated to particular land features, like the various Texas salamander species found among karst features in Travis and Williamson counties.

But it's not so easy for generalist species with large geographic and habitat ranges, like the tricolored bat. The tricolored bat's geographic range encompasses much of the eastern United States. According to the U.S. Fish and Wildlife Service, the tricolored bat will use both dead and living trees (of a variety of species) with living and dead leaf clusters. Large tracts of unbroken forest and riparian areas are also suitable habitats for the species. Naturally, transmission lines that must traverse multiple miles will have a non-zero chance of intersecting tricolored bat habitats. It is recommended that engineers and planners seek an environmental consultant to explore options regarding permitting and to accurately determine if a project might affect a listed species. Extra effort here could very well prevent project timeline hangups during the permitting process.

Understanding the conditions of NWP 58 and what language to be attentive to will be crucial if Texas is to meet its growing water infrastructure needs. USACE permitting is daunting. But if we understand where exactly the permitting process is permissive and constrictive, Texas engineers can realize a clearer path forward toward satisfying this infrastructure need.