Mid Coast Basin – Streamflow, River Stage & Tide Gages

About the Mid Coast Basin

Oregon’s Mid Coast basin covers the rain-fed rivers that drain the central Coast Range directly to the Pacific. The Oregon Water Resources Department’s Mid Coast Basin runs from Cascade Head and the Salmon River south past Florence to the Siltcoos and Tahkenitch lakes, and includes the Salmon, Siletz, Yaquina, Alsea, Yachats and Siuslaw watersheds and many small coastal streams. Its rivers have no large dams, so the flow records show natural winter-rain and summer-low-flow patterns. River Flow Planner covers 15 active USGS and OWRD gages here, from small headwater creeks such as East Fork Lobster Creek to the Siletz River at Siletz (record since 1905) and the Alsea River near Tidewater (record since 1939). Four of the USGS gages began in 2024, and the Siuslaw River at Florence estuary gage (river stage only) began in 2026, so their statistics are preliminary. It also covers 15 NOAA tide stations in Siletz Bay, Depoe Bay, Yaquina Bay, Alsea Bay and the Siuslaw River estuary: South Beach on Yaquina Bay measures water levels, and the other 14 are NOAA tide prediction stations.

What River Flow Planner shows for each gage

Each gage page turns the agency’s full daily record into planning tools for fishing, rafting, kayaking, swimming, irrigation and in-stream work:

• Summary hydrograph of typical flows through the year
• Percent of time flows fall within a range you choose
• Likely range of flows on future dates you pick
• How a recent period compares with normal, plus a year-by-year spaghetti plot
• Flood frequency statistics for USGS gages with peak-flow records
• CSV downloads and links to current real-time data and short-term forecasts
• For NOAA tide stations: a tide forecast chart and tide calendar for dates you pick, the highest and lowest tides of the next 5 years, and, at South Beach, how often the tide reaches levels you choose

Salmon River

Siletz River

Yaquina River

Alsea River

Yachats River

Big Creek

Siuslaw River

Tide Stations (NOAA)

Listed north to south, from the Salmon River estuary to the Siuslaw River. Tide heights are in feet above mean lower low water (MLLW) unless you choose another datum.

Other basins

Rogue River Basin · Klamath River Basin · Deschutes River Basin · North Coast Basin · Umpqua River Basin · South Coast Basin · Willamette River Basin · Sandy River Basin · Hood River Basin · John Day River Basin · Umatilla River Basin · Grande Ronde River Basin · Powder River Basin · Malheur River Basin · Owyhee River Basin · Malheur Lake Basin · Goose & Summer Lakes Basin