Final notice and public explanation of a proposed activity in a 100-year floodplain and wetland

Posted by City Hall on Jul 17, 2023

To:  All interested Agencies (DEQ, DSL, HUD, NOAA/NMFS, ODFW, and USACE) Groups and Individuals


This is to give notice that the City of Vernonia, acting as the Responsible Entity under Part 58, has conducted an evaluation as required by Executive Order 11988 and 11990, in accordance with HUD regulations at 24 CFR 55.20 Subpart C Procedures for Making Determinations on Floodplain Management and Wetlands Protection. The activity is funded under the Community Development Block Grant program under project number P21005. The proposed project is located within Vernonia city boundaries in the City of Vernonia, Columbia County. This project is categorized as a linear infrastructure project with a focus on improving the public sewer system in the western portion of town. Currently, the sewer system is under capacity in certain locations and there is a resulting Sanitary Sewer Overflow which poses a health hazard. At the same time, the system becomes excessively worn by the experienced use. Improvements to the sewer line are intended to start at the Clatsop St intersection with Weed Ave and flow toward the existing sewer in Springboard Ln. The existing sewer flowing south will be deepened and renovated with a larger pipe to provide greater capacity through Adams Ave to the intersection with Cougar St. A new pump station will be installed near the Adams Ave and Cougar St intersection to replace the existing pressurized connection east of Rock Creek. From this new pump station, all of western Vernonia will be connected to the sewer lagoon via a new line- minimizing demand on the existing pump station and increasing capacity as needed. Much of the proposed work occurs within the Rock Creek 100-year floodplain. Given that the proposed line will follow the existing sewer alignment, it will also bisect a wetland located on lot 200.These improvements will include about 4,000 linear feet of gravity sewer pipe and 3,200 linear feet of pressurized sewer pipe. Out of the overall 37,000 square feet of impact, 33,000 square feet (0.76 acres) will be located within the floodplain. This work will also include 93 square feet of work within the mentioned wetland along with additional excavation which will restore the wetland to natural conditions.

The City of Vernonia, as the Responsible Entity, has considered the following alternatives and mitigation measures to be taken to minimize adverse impacts and to restore and preserve natural and beneficial values:

Work within the floodplain is inevitable due to the expansive nature of Rock Creek’s floodplain to the east and west. A “No Work” alternative was considered to eliminate any effects, however this would result in no adjustment to the sewer system and the current issues would persist. Alternative routing and construction measures were also considered to circumnavigate effects to the floodplains and wetland, however the routing would result in additional impacts to Bear Creek and would still require work within the floodplain. The proposed project has been designed to minimize impacts to all present sensitive lands. By following the existing sewer alignment, it is believed that impacts will be minimized to just be temporary and related to the construction activity. This will eliminate the need for additional trenching or related impacts within the floodplain and other sensitive lands. Upon completion of the sewer work, conditions at the surface will be restored to existing or better conditions in an effort to preserve vegetative benefit. During construction, erosion and sediment control measures will be implemented to minimize the effects of earthwork on the surrounding areas. Federal parameters known as SLOPES have also been implemented in the design and will be followed during construction to minimize any adverse effects to the sensitive lands.


The City of Vernonia,has reevaluated the alternatives to building in the floodplain and wetlands and has determined that it has no practicable alternative.  Environmental files that document compliance with steps 3 through 6 ofExecutive Order 11988 and 11990, are available for public inspection, review and copying upon request at the times and location delineated in the last paragraph of this notice for receipt of comments. 


There are three primary purposes for this notice.  First, people who may be affected by activities in floodplains and wetlands and those who have an interest in the protection of the natural environment should be given an opportunity to express their concerns and provide information about these areas. Second, an adequate public notice program can be an important public educational tool. The dissemination of information and request for public comment about floodplains and wetlands can facilitate and enhance Federal efforts to reduce the risks and impacts associated with the occupancy and modification of these special areas. Third, as a matter of fairness, when the Federal government determines it will participate in actions taking place in floodplain and wetlands, it must inform those who may be put at greater or continued risk.


Written comments must be received by the City of Vernonia at the following address on or before July 28th, 2023: 

Josette Mitchell

1001 Bridge St.

Vernonia, OR 97064


and (503) 429 5291


Attention: Josette Mitchell, City Administrator


A full description of the project may also be reviewed from 9:00 AM to 5:00 PM at 1001 Bridge St, Vernonia OR 97064.  Comments may also be submitted via email at

Date: July 17, 2023