Determining Ordinary High Water Corps of Engineers and Dept. of State Lands Jurisdictional Determinations on non-Tidal Waterways ACEC Frannie Brindle Natural Resource Unit Manager, ODOT Technical Services

Dept. of State Lands and Corps of Engineers

OHW is Defined by Field Characteristics

Drift material (or wrack) in fence? Clear line impressed along shore? Antelope Creek, Jackson Co. March 2006

Field Characteristics Culvert staining–not appropriate for determining fish passage design criteria

Relation to Other ‘Lines’ 2-year flood elevation –Calculated based on modeling –OHW is usually lower on the bank than the 2-year Bank full stage –Often used interchangeably with OHW in literature –Channel forming flows –Defined by DSL as the two-year recurrence interval flood elevation Edge of Water Top of bank –Easily identifiable on some streams –OHW is usually below the top of the bank

Context In-water work timing Resource Impacts Fish Passage Design

Procedures Flag OHW in field (flag only one side of stream if access is limited and project line to the other side in CAD) Use painted stakes or flags where possible Take photos up- and down-stream showing flag placement

Procedures (cont) Complete form: –OHW field characteristics observed –If 2-year used instead, should be stated Develop site sketch showing flag locations, photo-points Final Documentation includes OHW Determination Form, Photos, Site Sketch

Completing the Form

2 Sample Site Sketch Low hanging vegetation- willows, other riparian Steep bank- visible indicators N Elevation point flow P1 P2, 3