Lower Willapa River measurement campaign 2025-2026
Data files
Jun 18, 2026 version files 11.09 MB
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lowill_totalwaterlevel_dataset.csv
11.08 MB
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README.md
12.86 KB
Abstract
This dataset contains continuous water level measurements collected along the lower Willapa River and adjacent water bodies near South Bend and Raymond, Washington, as part of a tidal-fluvial field measurement campaign (2025-2026). Sensors were deployed at 13 locations spanning three regions: the Willapa River main stem, the Willapa River South Fork, and Skidmore Slough. Measurements were recorded at 5-minute intervals using pressure-based sensors (TD-Diver, HOBO U20, In-Situ Rugged Troll 100, YSI CTD) and radar water level sensors (Tolthawk). Raw absolute pressure data were converted to Total Water Level (TWL) referenced to the NAVD88 vertical datum where possible using atmospheric pressure corrections from the NOAA Toke Point gauge (Station 9440910) and RTK-GPS survey elevations collected with an Emlid RS3 and Emlid RX. A series of quality control measures were used to produce the TWL dataset. This dataset is intended to support analysis of tidal-fluvial dynamics and compound flooding in the lower Willapa River system. This dataset was supported by the Pacific Conservation District and Pacific County Emergency Management Agency, whose assistance with field deployment and connections to local community members were invaluable.
This README contains all river total water level data for the Lower Willapa River Measurement Campaign (2025–26) by the UW Cascadia Coastlines and Peoples Hazards Research Hub team. This dataset was supported by the Pacific Conservation District and Pacific County Emergency Management Agency, whose assistance with field deployment and connections to local community members were invaluable.
Locations
All sensors were deployed either within or nearby the towns of South Bend and Raymond, Washington. For the purposes of this field campaign, they are organized in the following regions:
- Willapa River (abbreviated prefix "WR" in datasets)
- Willapa River South Fork (abbreviated prefix "SF" in datasets)
- Skidmore Slough (abbreviated prefix "SS" in datasets)
The coordinates of each deployment can be found in the Sensor Metadata section below.
Sensor Metadata
Below is the metadata for each sensor location listed in lowill_totalwaterlevel_dataset.csv:
| Field | WR01 | WR02 | WR03 | WR04 | WR06 | WR07 | WR08 | SF01 | SF02 | SF03 | SS01 | SS02 | SS03 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Timezone | PST | PST | PST | PST | PST | PST | PST | PST | PST | PST | PST | PST | PST |
| Start Date | 11/8/25 | 11/7/25 | 11/6/25 | 11/6/25 | 11/6/25 | 11/25/25 | 11/25/25 | 11/7/25 | 11/7/25 | 11/25/25 | 11/8/25 | 11/8/25 | 11/8/25 |
| End Date | 4/30/26 | 4/30/26 | 3/8/26 | 3/8/26 | 3/8/26 | 1/12/26 | 1/28/26 | 3/8/26 | 1/12/26 | 3/8/26 | 3/9/26 | 3/8/26 | 3/9/26 |
| Duration | 173 days | 174 days | 122 days | 122 days | 122 days | 48 days | 64 days | 121 days | 66 days | 103 days | 121 days | 122 days | 121 days |
| Frequency | 5 min | 5 min | 5 min | 5 min | 5 min | 5 min | 5 min | 5 min | 5 min | 5 min | 5 min | 5 min | 5 min |
| Units | metric | metric | metric | metric | metric | metric | metric | metric | metric | metric | metric | metric | metric |
| Datum | NAVD88 | NAVD88 | NAVD88 | NAVD88 | NAVD88 | NAVD88 | N/A | NAVD88 | NAVD88 | N/A | NAVD88 | NAVD88 | NAVD88 |
| Lat | 46°39'59.76"N | 46°41'20.55"N | 46°40'50.00"N | 46°41'02.73"N | 46°40'45.00"N | 46°39'53.90"N | 46°39'04.20"N (approx) | 46°40'57.99"N | 46°40'01.99"N | 46°37'45.00"N (approx) | 46°40'20.07"N | 46°40'11.00"N | 46°40'15.54"N |
| Lon | 123°47'38.87"W | 123°43'21.11"W | 123°42'06.00"W | 123°40'47.10"W | 123°40'20.99"W | 123°40'23.53"W | 123°40'32.45"W (approx) | 123°43'59.68"W | 123°43'23.99"W | 123°41'52.00"W (approx) | 123°46'40.99"W | 123°46'35.84"W | 123°46'35.61"W |
| Sensor Type | Tolthawk | Tolthawk | TD-Diver | TD-Diver | YSI CTD 600LS (pre-12/14/25); In-Situ Rugged Troll 100 (post-12/14/25) | YSI CTD 600LS | YSI CTD 600LS | TD-Diver | TD-Diver | HOBO Water Level Logger U20-001-01-TI | HOBO Water Level Logger U20-001-01-TI | HOBO Water Level Logger U20-001-01-TI | HOBO Water Level Logger U20-001-01-TI |
| S/N | N/A | 334406048 | FS029 | FS064 | 2005 (pre-12/14/25); 632743 (post-12/14/25) | 2006 | 2004 | FS041 | FS040 | 1289199 | 1126515 | 1126509 | 1126511 |
Sensors
Measurement frequency: 5 minutes
Sensor Types
TD-Diver
- Measures: pressure, temperature
HOBO Water Level Logger U20-001-01-TI
- Measures: pressure, temperature
In-Situ Rugged Troll 100
- Measures: pressure, temperature
Tolthawk
- Measures: water level
- This data is reported in real-time and can be found at the following links:
YSI CTD 600LS
- Measures: pressure, temperature, salinity
Measurements and Datasets
The majority of data collected were absolute pressure measurements, with several locations also measuring temperature and salinity. Absolute pressure was converted to Total Water Level (TWL) using atmospheric pressure from the NOAA Toke Point gauge, with in-situ temperature and salinity measurements applied at locations where they were available. The survey data was used to convert TWL to TWL relative to the NAVD88 vertical datum. A complete dataset with all conversion steps included can be found in the repository (https://github.com/skbugbee/LoWill-Measurements-2025-26.git), along with further information on the measurement campaign including floodplain instrumentation.
Installation Techniques
Subtidal Sensors
Sensors installed subtidally were primarily attached to historic pilings along the river and within sloughs. To capture the full tidal range, the sensors were fastened to the bottom of mounts and deployed at the lowest tide of the day. Initial mounts were made of 8-foot PVC and slotted zinc-coated steel angles before switching to 8' aluminum tubing for the majority of the field campaign. Sensors were fastened to mounts with stainless steel hose clamps and further secured with zip ties and electrical tape as needed. Similarly, mounts had slots drilled at the top and 1–1.5' from the top for stainless steel hose clamps to loop through for fastening to pilings. Nails were hammered both 1 ft and 2 ft above the top of mount to ensure any movement from initial deployment position. Instances of significant movement are further discussed in the Uncertainty section below.
Radar Sensors
Radar sensors were installed at two locations: Bendiksen's Landing (WR01) and Raymond's Landing (WR02). As these sensors cannot become submerged, they were attached at high elevations. The sensor at Bendiksen's Landing was attached to the dock and the sensor at Raymond's Landing was attached to the top of a dock piling.
Trip Summaries
A location being "serviced" means a sensor was retrieved, downloaded, and redeployed at that location. A location being "retrieved" means a sensor was retrieved and no sensors were redeployed. Some locations are instrumented with multiple sensors; this summary does not distinguish between them.
Recon (10/21–10/22)
- Deployed: WR03
First Deployment (D1) — 11/6–11/8
- Serviced: WR03
- Deployed: WR01, WR02, WR04, WR05, WR06, SF01, SF02, SS01, SS02, SS03
Second Deployment (D2) — 11/25
- Deployed: WR07, WR08, SF03
Third Deployment (D3) — 12/14–16
- Retrieved: WR05
- Serviced: WR01, WR03, WR06
- Deployed: WR07
Fourth Deployment (D4) — 1/11–12
- Serviced: WR03, WR04, WR06, WR07, SF01, SF02, SF03
Fifth Deployment (D4.5) — 1/28
- Serviced: WR08
Sixth Deployment (D5) — 3/8–9
- Retrieved: WR01
- Serviced: WR03, WR04, WR06, WR07, SF01, SF03, SS01, SS02, SS03
Survey
Surveys were completed using an Emlid RS3 mounted on a 1.8 m collapsible survey pole and an Emlid RX mounted on a 1.99 m survey pole. The RS3 connected to one of three subnets of the Washington State Virtual Reference Network depending on connection: PACWAVRSRTCM3 (primary), RYMD3, and RYMD_MSM. Surveys were collected with 30-second averaging, reported in meters referenced to Washington State Plane, Zone South (NAD83) for the horizontal, and NAVD88 (Geoid18) for the vertical. Survey data can be found in the GitHub repository.
Additional information:
- Emlid RS3 S/N: 8243CA3BAAD4E443
- Emlid RS3 survey pole length key:
- Fully extended: 1.8 m
- Bottom collapsed: 1.24 m (add 0.56 m to elev)
- Fully collapsed: 0.73 m (add 1.07 m to elev)
- Emlid RX S/N: 8243fa6e4a7a666e
Software
To program and download the sensor data, the following software was used:
- HOBOware — HOBO sensors
- Win-Situ 5 — In-Situ sensors
- Diver Office — Diver sensors
- Ecowatch Lite — CTD sensors
Uncertainty
Universal Uncertainty
Survey:
- While surveys were primarily conducted using the PACWAVRSRTCM3 subnet, both RYMD3 and RYMD_MSM subnets were occasionally used depending on connection at each site. Subnets for each survey are recorded in the survey data in the GitHub repository.
- Points were surveyed using a single 30-second average.
- The majority of surveys were measured indirectly at a distance from the sensor head. All differences were accounted for in post-processing and recorded in the deployment tracking sheet in the GitHub repository.
- The survey pole attached to the Emlid RS3 is collapsible. Corrections for surveys measured with the pole collapsed were accounted for in post-processing and recorded in the deployment tracking sheet in the GitHub repository.
Site-Specific Uncertainty
Survey:
Survey was not possible at two sites due to poor coverage: WR08 pressure and SF03 pressure.
WR03 pressure:
- Observed downslide of 3" from D1 to D3 retrieval.
- Observed downslide of ¾" from D3 to D4 retrieval. Redeployed at the original position.
WR08 pressure: Sensor was PVC-mounted to a tree within the channel with significant scour observed at the base.
SF03 pressure: Sensor was attached to a concrete block and wedged between two large rocks in the river far upstream. Upon retrieval at D5, the block had been rotated from horizontal to vertical orientation. The sensor was redeployed in the original position during D5.
SS03 pressure: Mount was switched to another nearby piling deeper into the channel at D4. Mount was surveyed in each position.
Sensors were deployed at 13 locations across the lower Willapa River main stem, South Fork, and Skidmore Slough between October 2025 and March 2026. Sensors were primarily mounted to historic pilings using aluminum or PVC tubing and stainless steel hose clamps. Measurements were recorded at 5-minute intervals. Sensor types included TD-Diver, HOBO Water Level Logger U20-001-01-TI, In-Situ Rugged Troll 100, Tolthawk radar gauges, and YSI CTD 600LS. Absolute pressure measurements were converted to Total Water Level using atmospheric pressure from the NOAA Toke Point gauge (Station 9440910) and temperature/salinity corrections where available. Sensor elevations were established where possible via RTK-GPS survey using an Emlid RS3 and Emlid RX connected to the Washington State Virtual Reference Network, with positions reported in NAVD88 (Geoid18).