A suite of geophysical methods was used along the Cedar River in Cedar Rapids, Iowa to support the hydrogeologic characterization of the alluvial aquifer associated with the river and to assess the area for suitability for larger-scale airborne geophysics. The aquifer is comprised of sand and gravel, interbedded with finer sediments, and underlain by carbonate-dominated bedrock. The aquifer is the principal source of municipal drinking water for the City of Cedar Rapids. The raw data files provided here include waterborne continuous resistivity profiling (CRP) and continuous seismic profiling (CSP) data, which were collected concurrently in April 2015, electrical resistivity tomography (ERT) profiles from April 2015, horizontal to vertical spectral ratio (HVSR) seismic from April 2015 and several borehole geophysical logs including nuclear magnetic resonance (NMR), gamma, and electromagnetic induction (EMI) from nine wells, collected in June, 2017. The CRP, ERT, and borehole logs measure the electrical properties of the subsurface, which can be related to stratigraphic layers. The HVSR, CSP, CRP and some of the borehole logs characterize the depth to bedrock. Collectively the suite of methods can help characterize the subsurface and map the extent of the sand and gravel aquifer. In addition, these geophysical measurements can be used to plan and to ground truth air-borne electromagnetic surveys.

In September 2018, approximately 13 miles of continuous seismic profiling (CSP) surveys were collected on the Des Moines River and Beaver Creek in Des Moines, Iowa. The swept frequency (chirp) CSP subbottom profiler was used to characterize the unconsolidated materials above the bedrock. The CSP subbottom profiler is an acoustic sound source that travels through the water column and reflects off the bottom and sub-bottom layers and is received at the transducer. Applying a water column velocity, the two-way travel time can be converted to distance. CSP methods provide the depth to water bottom, and when sufficient signal penetration is achieved, CSP can be used to delineate the depth of subbottom layers and topography of the bedrock surface. Data were collected concurrently with CRP methods. Both methods used the same .gps files for georeferencing. Starting and ending coordinates for each line are specified in the file "readme_CSP.txt". This data release contains the raw instrument files for each survey line converted to open-source files (.SGY), a comma separated values notes file (CSP_Archive_Notes_DesMoinesIA.csv), and a text file (readme_CSP.txt) file that explains data files and contains the processing references. Field notes taken at the time of data collection are not included in this data release but are available upon request.

In April 2015, a total of 34 passive seismic surveys were conducted in the Cedar River Floodplain. The horizontal-to-vertical spectral ratio (HVSR) method is a passive seismic technique that uses a three-component seismometer to measure the vertical and horizontal components of ambient seismic noise. Seismic noise in the range of approximately 0.1 to 1 Hertz (Hz) is caused by ocean waves, large regional storms, and tectonic sources. A resonance frequency (f0) is induced in the unconsolidated deposits when there is a substantial contrast (greater than 2:1) in shear-wave acoustic impedance between the overburden and the bedrock. The f0 is determined from the analysis of the spectral ratio of the horizontal and vertical components of the seismic data. The thickness of the overburden can be related to the f0. In general, lower f0 relates to thicker sediments, and higher f0 relates to relatively thinner overburden.

In April 2015, approximately 19 miles of continuous resistivity profiling (CRP) surveys were collected on the Cedar River in Cedar Rapids, Iowa. The CRP method was used to characterize the resistivity of the water column and subbottom materials. Five CRP profiles were collected concurrently with the continuous seismic methods. For this investigation, 11 electrodes spaced 10 m apart and mounted in a streamer were towed behind the boat and data were collected using the dipole-dipole array type. The first two electrodes, closest to the boat, were used to inject current into the water and subbottom materials, and eight electrical potential measurements were made using the remaining nine electrodes. With this system, a complete suite of measurements is collected every 2.8 seconds. Because the boat is moving at a slow rate of speed, a complete measurement is taken while the boat has moved about 3-5 m. In general, voltage measurements taken with larger electrode spacings extend deeper into the subsurface. The exact depth and resistivity are determined through a process of inversion. The raw CRP data are shared in this data release.

These data represent a Global Positioning System (GPS) survey generated September 20, 2023, using Trimble R10 Real-Time Kinematics (RTK) and Global Navigation Satellite Systems (GNSS). Survey extends along the Cedar River streambed in Cedar Falls, Iowa, where a wastewater treatment diffuser pipe is installed. Cross-sectional representations were produced to depict stream depth and streambed elevation. Cross-sectional data should be interpreted from a downstream perspective.

These data represent a Global Positioning System (GPS) survey generated September 20, 2023, using Trimble R10 Real-Time Kinematics (RTK) and Global Navigation Satellite Systems (GNSS). Survey extends along the Cedar River streambed in Cedar Falls, Iowa, where a wastewater treatment diffuser pipe is installed. Cross-sectional representations were produced to depict stream depth and streambed elevation. Cross-sectional data should be interpreted from a downstream perspective.

This data release contains a set of permeameter test data collected in February and March of 2014 on the Cedar River near Cedar Rapids, Iowa. The permeameter tests were performed in proximity to five horizontal collector wells (HCs) 1, 2, 3, 4, and 6, and three vertical wells that are operated by the City of Cedar Rapids. Each dataset represents groundwater levels over time while individual HC and a few selected vertical wells (S10, S18, S23) had pumps turned on or off to look at the response of the streambed sediments as it relates to the operations of HCs and vertical wells. Three permeameter test locations at the HC2 site and four at the HC1, 3, 4, and 6 were selected across the Cedar River for permeability tests. At each permeameter test location, a hole was drilled through the ice, and a 2-inch clear tube was inserted into the streambed so that the bottom of the tube was filled with streambed sediments and the resulting head after equilibration was representative of the groundwater head. Then, water was poured into the clear tube to measure the groundwater head using submersible pressure transducers recording at 5 second intervals. It was assumed that the water level of the stream was constant during the permeameter test (Chen, 2000). This data release contains the raw water level data in an Excel sheet (PermTestsCalcsAll2014.xlsx), a file (Readme_CR_PermeameterTestData.txt) that provides details about all the files, and an Environmental Systems Research Instituite (ESRI) shapefile (.shp) and its associated files. Reference: Chen, X., 2000, Measurement of streambed hydraulic conductivity and its anisotropy: Environmental Geology, v. 39, p. 1317-1324. [Also available at https://doi.org/10.1007/s002540000172.]

This data release presents a peak-flow frequency analysis by the U.S. Geological Survey that was based on on methods described by Eash and others (2013) for streamgages 05458300 Cedar River at Waverly, Iowa; 05458500 Cedar River at Janesville, Iowa; and 06606600 Little Sioux River at Correctionville, Iowa. These methods are used to provide estimates of peak-flow quantiles for 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs). Annual peak-flow data used in the peak-flow frequency analysis for these streamgages were retrieved from the U.S. Geological Survey National Water Information System webpage (U.S. Geological Survey, 2020) and used with USGS flood-frequency analysis software PeakFQ (Veilleux and others, 2014). This data release contains annual peak-flow data (Iowa_ffa_2019_WATSTORE.txt), PeakFQ specifications (Iowa_ffa_2019.psf), and a series of tables describing the methods and results of the peak-flow frequency analysis (Iowa_ffa_2019.xlsx). References Cited: Eash, D.A., Barnes, K.K., and Veilleux, A.G., 2013, Methods for estimating annual exceedance-probability discharges for streams in Iowa, based on data through water year 2010: U.S. Geological Survey Scientific Investigations Report 2013-5086, 63 p. with appendix., http://pubs.usgs.gov/sir/2013/5086/. U.S. Geological Survey, 2020, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed June 25, 2020, accessed June 25, 2020, at https://doi.org/10.5066/F7P55KJN. Veilleux, A.G., Cohn, T.A., Flynn, K.M., Mason, R.R., Jr., and Hummel, P.R., 2014, Estimating magnitude and frequency of floods using the PeakFQ 7.0 program: U.S. Geological Survey Fact Sheet 2013–3108, 2 p., https://dx.doi.org/10.3133/fs20133108.

These data represent a Global Positioning System (GPS) survey generated using a Trimble R10 Real-Time Kinematic (RTK) and Global Navigation Satellite Systems (GNSS). The Ssurvey extends along the Cedar River streambed in Cedar Falls, Iowa, where a wastewater treatment diffuser pipe is installed. Cross-sectional representations were produced to depict stream depth and streambed elevation. Cross-sectional data should be interpreted from a downstream perspective.

A field survey of the lower Cedar River from Landsburg to Renton, WA was conducted on 29 April 2010 from a raft using real-time kinetic global positioning system to determine horizontal location and water surface elevation and a pressure transducer to measure depths along the thalweg of the river. These data were averaged over 100 m intervals to generate water surface elevations, river bed elevations, and depths at regular 10-meter intervals. The water surface and river bed gradients were calculated using the water surface elevations 10 m upstream and 10 m downstream of each point. Each point was assigned as a pool, riffle, or other type. Observations of salmon redds during the fall of 2010 are indicated.