DOI: 10.6078/d1gt31
title: Flow augmentation from off-channel storage improves salmonid habitat and survival

description: In the Western United States, juvenile salmon and steelhead are especially
 vulnerable to streamflow depletion in the dry season. Releasing water from
 off-channel storage is a method of streamflow augmentation increasingly
 used to offset the impacts of anthropogenic flow alteration. However, to
 date, no studies have evaluated the effects of these small-scale flow
 augmentations on salmonids. Here we quantify the effects of one such
 augmentation project on habitat connectivity, water quality, invertebrate
 drift, juvenile salmonid movement, and survival. Our study took place in a
 Northern California stream and included an unusually wet summer (2019) and
 a more typical dry summer (2020). We found that differences in ambient
 streamflows between the two years mediated the physical and ecological
 effects of a 13.9 L/s augmentation treatment. In the dry year, flow
 augmentation significantly improved dissolved oxygen and habitat
 connectivity at sites &gt; 1.5 km downstream from the point of
 augmentation and had a marginal warming effect on stream temperature.
 During the wet year, both dissolved oxygen and water temperature effects
 were negligible. In both years, augmentation had a small but positive
 effect on invertebrate drift. Inter-pool movement of juvenile steelhead
 (Oncorhynchus mykiss) and stocked Coho Salmon (O. kisutch) increased due
 to augmentation during the dry summer. Flow augmentation also increased
 the survival probability for salmonids, with a larger effect during the
 dry summer (24% higher survival for Coho and 20% higher for steelhead),
 than during the wet summer (when no effect was observed for steelhead
 survival and Coho Salmon survival increased by 11%). This study indicates
 that appropriately designed and timed flow augmentations can improve
 conditions for rearing salmonids in small streams, particularly during dry
 years. More broadly it provides empirical evidence that efforts to restore
 summer streamflow in small, salmon-bearing streams can yield significant
 ecological benefits.
description: These data were generated to investigate the effect of flow
 augmentation into a small, intermittent stream: Porter Creek in
 Healdsburg, California, USA. The flow augmentation experiment released
 13.9 L/s of water from an off-stream pond into the stream channel for one
 month in the summers of 2019 and 2020. Our objectives were (1) to evaluate
 the spatial effects of flow augmentation on habitat connectivity and (2)
 to measure the response of physical and biotic variables that influence
 the rearing profitability and fitness of summer-rearing salmonids to a
 flow manipulation of known proximity and magnitude. To address the first
 objective, we measured the extent of the wetted channel from the point of
 augmentation downstream to the creek outlet. Wetted channel extent below
 the augmentation release point was compared to an unaltered, control reach
 extending approximately 2 km upstream of the augmentation. To address the
 second objective, we estimated how flow augmentation affected dissolved
 oxygen, water temperature, hydraulic habitat, invertebrate drift, and
 inter-pool movement, growth, and survival of salmonids.
description: # Flow augmentation from off-channel storage improves salmonid habitat and
 survival [https://doi.org/10.6078/D1GT31](https://doi.org/10.6078/D1GT31)
 ## Description of the data and file structure #### Data in this dataset
 include three main types: 1. Raw data from continuous monitoring devices
 1. Onset HOBO U20 water level loggers (Water level (m), and Water
 Temperature (C)) 2. Onset HOBO U26 dissolved Oxxygen data loggers (DO
 (mg/L) and Water Temperature (C)) 3. PIT Tag Antenna Detections (Date,
 Sitecode, Tag number, Species, Origin) 4. Augmentation and Streamflow data
 from stream gages 2. Measured Data 1. Benthic Invertebrate Drift Data
 (Stream, reach, site, date, taxa, length (mm), weight (mg) plus metadata
 files) 2. Pool Habitat data (hand measurements of dissolved oxygen (mg/L),
 water depth, water temperature velocity) 3. Wetted Habitat Data (e.g.
 Site, date, conditions (wet, dry, intermittent), location, rkm length) 4.
 Electrofishing data (e.g. site, crew, data, pass, voltage, species, length
 (mm), weight (g), and metadata). 5. Wanding Data 3. R Scripts of data
 analysis and figures 1. Note file pathnames will need to be changed, but
 raw data for analysis and figures is included in each folder. ### Folder
 Information 1. Augmentation and Streamflow 1. Raw streamflow data for 2019
 and 2020 at four gauged locations in Porter Creek 2. Estimated streamflow
 in control reach for 2019 3. Compiled Augmentation Data 4. R Code for
 analysis. 2. BMI Drift 1. Raw Drift Data from BMI analysis 1.  Header
 definitions 1. | Header | Definition | | :-------------------------------
 | :------------------------------------------------------- | | Reach |
 Unique ID for each study Reach | | Pool\_ID | Unique ID for each study
 Reach | | Time\_in | time drift nets were installed | | Time\_out | time
 drift nets were removed | | cm\_from Top BAR | distance (cm) from the top
 of drift net to water surface | | Duration\_hrs | duration of drift sample
 | | Drift\_Vel\_1\_ft\_s | average water velocity (ft/s) at mouth of drift
 net | | Vel\_1m\_from\_drfit\_net\_ft\_s | average water velocity (ft/s)
 1m downstream from net | | Vel\_2m\_from\_drfit\_net\_ft\_s | average
 water velocity (ft/s) 2m downstream from net | |
 Vel\_3m\_from\_drfit\_net\_ft\_s | average water velocity (ft/s)3m
 downstream from net | 2. Drift Metadata (duration, the velocity (ft/s) at
 net, notes, etc.) 1. Header definitions 1. | Stream | name of stream | |
 :---------- |
 :---------------------------------------------------------------------------------------------------- | | Reach | unique ID for each Reach | | Pool | unique ID for each Pool | | Date | | | ID | lowest taxonomic level we could ID | | Order | Order of invertebrate taxonomy | | Size Class  | length in mm | | Number | number counted at each length (mm) | | lna | regression coefficient to convert length to mass | | b | regression exponent to convert length to mass | | biomass  | total biomass (mg) computed for each unique combination of order, number, and size within each sample | | Notes | | 3. R Code for analysis. 3. Fish Movement and Growth 1. Antenna Detections (named: 2019_2020_movement.csv) 1. Header Definitions 2. | Year | year | | :-------------- | :----------------------- | | Species\_Lookup | species name | | Origin | wild or hatchery fish | | PITNumber | PIT ID | | Site | ID for sampling location | | Date | Date | 2. Dates when block nets were installed 3.  Electrofishing data for growth 1. Header definitions 2. | Tributary | Stream sampled | | :----------- | :------------------------------------------------------------------------- | | ReachName | Reach ID | | Crew | initials of crew | | Date | | | AirTemp | AirTemp (C) | | WaterTemp | WaterTemp (C) | | HabitatType | Pool or riffle | | PassEffort | seconds for each electrofishing pass | | Voltage | voltage (Volts) (DC) of backpack electrofisher | | FishNumber | unique ID for each fish sampled in each unit and date | | Species | Species | | LifeStage | life stage of salmonids | | ForkLength | ForkLength in mm | | Weight | Weight in grams | | PITNumber | PIT Tag ID | | Mortality | did the fish die | | Deformity | was the fish deformed | | SampleInjury | was the fish injured during e-fishing | | ReachID | unique Reach ID | | RiverKmLo | how far (km) was the unit from the mouth of the tributary | | Weather | weather conditions during sampling | | StartTime | start time of sample | | Origin | wild or hatchery origin fish | | Fat1-8 | was fat sampled and if so the body fat estimate of each sample (1-8 total) | 4. R Code for analysis of detections and growth 4. Flow Temperature, DO, Riffle crest thalweg (RCT) Depth 1. Dissolved Oxygen (D) Files from Data loggers 2. Stage Files from Data Loggers 3. Corrected files for input to R 4. R Code for analysis of DO, Water Temperature, and RCT Depth 5. Gant Chart Data and Study Metadata 1. Project metadata (start and end dates for each measurement activity) 6. Hand Measurement Habitat Data 1. Pool-specific habitat data: e.g., staff plate readings, DO, riffle crest, and water temperature measurements and notes 7. Pool Velocity Data 1. Date and Pool specific Velocity measurements 2. R Code for analysis of Pool Velocity. 8. Wetted_Habitat 1. Wet-Dry Mapping Data (also available on Sea Grant Dashboard) 1. Header Definitions 2. | tributary | Stream the data was collected on | | :------------------ | :------------------------------------------------------------- | | surveydate | date surveyed | | field\_condition | whether each reach was following "wet", intermittent, or "dry" | | agency | Which agency collected the data | | flowid | unique ID for each sample collected | | gps\_method | how the GPSd data was collected | | rkm\_length | length of surveyed reach | | salmonids\_observed | 1 or 0 for observed salmonids | | crew | initials of crew | | comments | comments | 1. [https://russianrivercoho.maps.arcgis.com/apps/dashboards/6064be512385427a860af7291bec760f](https://russianrivercoho.maps.arcgis.com/apps/dashboards/6064be512385427a860af7291bec760f). 2. R Code for analysis Wet Dry Mapping Data 9. Survival 1. Data on Porter Creek Survival analysis, and effect size 1. Header definitions 2. | Species | Species | | :---------- | :-------------------------------- | | Year | Year | | Reach | above or below flow augmentation | | S\_Interval | before or after flow augmentation | | S | survival estimate | | SE\_S | standard error | | FigLow95\_S | lower 95th percentile | | FigUp95\_S | upper 95th percentile | 2. R Code for Survival figures ## Additional information 1. The Wet-Dry Mapping data is available on Ca Sea Grant's Dashboard at [https://russianrivercoho.maps.arcgis.com/apps/dashboards/6064be512385427a860af7291bec760f](https://russianrivercoho.maps.arcgis.com/apps/dashboards/6064be512385427a860af7291bec760f). 2. Any empty (blank) cells in .csv files associated with this dataset mean that no data was collected for that variable on that date/time