HW1 – Time Series Streamflow Resampling

Overview

This project analyzes daily streamflow data from four USGS gaging stations in the Upper Colorado River Basin across a common six-year period (2014–2020). The goal is to demonstrate temporal resampling at multiple scales and compare hydrologic behavior between reservoir-regulated and headwater systems.

The workflow is fully reproducible using Python, Pandas, and Matplotlib within a controlled conda environment.

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Study Sites

Station ID	Name	Role
09180000	Dolores River Near Cisco, UT	Regulated Tributary
09180500	Colorado River Near Cisco, UT	Reservoir-Regulated
09183600	Mill Creek Below Sheley Tunnel, Near Moab, UT	Headwater Catchment
09185600	Colorado River at Potash, UT	Downstream Mainstem

For comparative analysis, USGS 09180500 (Colorado River Near Cisco) serves as the reservoir-regulated reference site and USGS 09183600 (Mill Creek Below Sheley Tunnel) as the headwater catchment.

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Methods

Daily discharge data (ft³/s) were obtained from the USGS National Water Information System (NWIS). Records were loaded into Python, converted to datetime-indexed DataFrames, and subset to the shared 2014–2020 overlap period.

Temporal aggregation was performed at three scales:

• Weekly – mean discharge (ft³/s)
• Monthly – volumetric totals (ft³/month)
• Annual – volumetric totals (ft³/year)

Wet and dry years were identified from annual volumetric discharge totals. Daily hydrographs were grouped by day of year to construct a six-year min–max envelope, with wet and dry year traces overlaid for comparison.

All analyses were performed in a Jupyter Notebook and version-controlled with GitHub.

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Results

Temporal Resampling Across Scales

Aggregating from daily to weekly to monthly scales progressively smooths the hydrograph signal. Reservoir-regulated and downstream mainstem sites show amplified seasonal peaks relative to the headwater catchment, reflecting the influence of upstream storage on flow timing and magnitude.

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Wet vs. Dry Year Hydrographs

Wet (2019) and dry (2014) year hydrographs are compared against the six-year daily min–max envelope. The reservoir-regulated site exhibits peak attenuation and sustained late-season flow, while the headwater site shows a sharper snowmelt pulse and faster recession — a pattern consistent with direct runoff response and minimal upstream storage.

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Repository Structure

hw1-timeseries-streamflow-resampling/
│
├── data/
│   ├── raw/                 # Raw USGS streamflow data
│   └── processed/           # Processed, overlapping 6-year dataset
│
├── notebooks/
│   └── 01_data_acquisition_processing.ipynb
│
├── figures/                 # Output figures
│
├── environment.yml          # Conda environment specification
├── .gitignore
└── README.md

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How to Reproduce

1. Clone the repository

git clone <your-repository-url>
cd hw1-timeseries-streamflow-resampling

2. Create the conda environment

conda env create -f environment.yml

3. Activate the environment

conda activate hw1-streamflow

4. Launch Jupyter

jupyter notebook

5. Open and run the notebook

notebooks/01_data_acquisition_processing.ipynb