Rio Grande Project Drought Resilience Efforts (DRE) Initiative

Modeling for the Rio Grande Project Drought Resilience Efforts (DRE) Initiative

Repo overview

This repo contains a minimal setup for running a rainfall/runoff workflow with gridded inputs.

• run.sh
  main runner script containing the shell commands for running grass modules in sequence.

• data/
  rainfall depth inputs (text files), e.g. rain_1h_depths.txt, rain_24h_depths.txt.

• spatial_data/
  geospatial rasters used by the workflow:

  • dem.tif: original dem
  • dem_modified.tif: processed dem used for modeling
  • esa.tif: land cover raster
  • n_low.tif: manning n (low roughness) raster
  • hsg.md: notes/metadata for hydrologic soil group inputs

• LICENSE
  project license.

PRISM rainfall processing workflow

This repo also includes a GRASS + Bash + R workflow to download PRISM climate rasters and compute area-weighted watershed time series for precipitation and temperature.

Scripts

• import_prism_rasters.sh — import PRISM zip rasters into GRASS
• create_prism_grid_4km.sh — build PRISM 4 km grid vector
• union_prism_area_grid.sh — intersect grid with watershed and compute cell areas
• calc_weighted_avg_prism.sh — compute area-weighted daily ppt/tmax/tmin
• prec_analysis.R — precipitation statistics and plots

Run order

Run inside an active GRASS GIS session:

1. Download PRISM rasters

m.prism.download dataset=0,2,4 start_date=1990-01-01 end_date=2023-12-31

2. Import and process

bash import_prism_rasters.sh
sh create_prism_grid_4km.sh
sh union_prism_area_grid.sh
sh calc_weighted_avg_prism.sh

3. R analysis

Rscript prec_analysis.R

SIMWE discharge sum along a user-defined line (GRASS + Bash)

This repo includes a Bash script that automates a SIMWE (r.sim.water) run and then computes the sum of discharge raster values within a buffered corridor around a line defined by two coordinates.

What it does

Given gridded inputs (DEM, dx, dy, Manning’s n) and a rainfall intensity:

1. Runs r.sim.water to generate depth and discharge rasters.
2. Builds a 2-point line vector from (x1, y1) → (x2, y2).
3. Buffers the line as a vector polygon (robust for short lines).
4. Rasterizes the buffered polygon to create a mask.
5. Extracts discharge values where the mask is present.
6. Calculates the sum of extracted discharge values for the last output timestep (equal to niterations).

Note: The “last timestep” discharge map q_<outprefix>.<niterations> exists only if niterations is a multiple of output_step.

Script

• simw_line_sum_pure.sh — pure Bash (no g.parser) SIMWE + line-buffer + discharge-sum workflow

Requirements

• GRASS GIS (with r.sim.water, v.in.ascii, v.buffer, v.to.rast, r.mapcalc, r.univar)
• A GRASS Location/Mapset containing the rasters:
  • elevation (DEM)
  • dx, dy
  • man (Manning’s n raster or constant)
• Coordinates x1,y1,x2,y2 in the same CRS as your GRASS Location.

Usage

Run inside an active GRASS session:

chmod +x simw_line_sum_pure.sh

./simw_line_sum_pure.sh \
  elevation=dem_3m_mod dx=dx_mod dy=dy_mod man=n_low \
  rain=23 niterations=60 output_step=60 nprocs=4 \
  outprefix=2y1h_mod \
  x1=-1030077.451885954 y1=1125099.4959982967 \
  x2=-1030095.7392827778 y2=1125112.068581797 \
  buffer=3