Humboldt supervisors approve steps to expand DD11 Sub 1 and seek bids for larger pipe

The Humboldt County Board of Supervisors voted to advance improvements to Drainage District DD11 Sub 1 Tuesday, approving specifications to bid the project using a 1-inch drainage coefficient and moving forward with a process to convert a 139‑acre privately tiled area into a county-maintained tile upon landowners’ signatures.

The board’s action follows an extended public hearing and technical presentation on proposed upgrades to the district’s main outlet. The project scope was shortened by roughly 600 feet from earlier designs, which lowered construction estimates. The presenter gave updated cost figures of about $700,000 for a design using a half‑inch drainage coefficient and about $811,000 for the 1‑inch option, down from earlier estimates of $787,000 and $941,000 respectively.

Why it matters: the project will alter how water drains across multiple farms in the district, change who pays assessments, and determine outlet capacity for adjoining private tile systems. Supervisors and landowners discussed how to apportion costs by parcel based on soils, distance to the improvement and expected benefit.

County staff described the project components and a proposed path for incorporating privately owned tile into the district. The presenter said a private tile 139 acres in size had not been included in earlier design assumptions and that if those acres are to be treated as district facilities they should be separately classified and assessed. "I misspoke at the meeting last two weeks ago ... I didn't include those acres," the presenter said, and advised the board that the parcel group could be classified as a separate district facility with its own assessment schedule.

Technical choices: county staff said the half‑inch design would begin with roughly a 30‑inch pipe; the 1‑inch design would begin with roughly a 36‑inch pipe and would require at least 3 feet of cover. The presentation noted opportunities to increase grade and adjust pipe sizing where the plan was shortened, producing cost savings. Staff also recommended bidding both concrete and plastic pipe options.

Assessments and annexation: staff outlined that construction costs located in secondary road right‑of‑way would largely be borne by the county roads budget, reducing the construction charge allocated directly to the closest 139 acres; however, those acres would still receive benefit and be part of any later reclassification. The board approved a separate procedural step to accept the privately owned tile into the county system contingent on signatures from all affected landowners; supervisors instructed staff to prepare paper agreements and record the adoption once signed.

Schedule and next steps: the county engineer said he would produce plans and specifications in one-to-two weeks and return to the board for approval to advertise. He estimated a typical advertisement window of about three weeks before bids are opened and said the county hopes to bid quickly to allow contractors to begin before winter.

Concerns raised: supervisors and landowners asked about fiber infrastructure, where staff said existing fiber is on the west side of the nearby intersection and recommended standard locates before construction. Landowners also pressed for clarity about which lateral connections would be included and how future lateral work would be assessed.

Votes at a glance: the board voted to (1) accept the procedural step to convert the 139‑acre private tile to a county main contingent on landowner signatures (motion carried), and (2) direct staff to prepare bid documents for the 1‑inch coefficient design with both plastic and concrete pipe options (motion carried).