San Francisquito Catchment - Controlled Rainfall Example

Purpose

This example presents a controlled rainfall-runoff simulation for the San Francisquito Creek catchment near Stanford, California. It shows how HydroPol2D responds on a real watershed to a storm whose timing and volume are known exactly.

Case setup

The case Stanford_30m_Website_100mmh_1h_24h uses:

Item	Value
Domain	San Francisquito Creek catchment, California, USA
Grid	30 m, NAD83 / California Albers (EPSG:3310)
Forcing type	Spatially uniform rainfall
Rainfall event	100 mm/h from 15 to 75 min (100 mm)
Simulation duration	24 h
Map output interval	15 min
Routing family	Local inertial
Outlet treatment	Perimeter outlet
Processes	Infiltration on; groundwater, evapotranspiration, snow and water quality off

Input data

Two inputs are maps (Figure 1):

• Terrain. The USGS 3D Elevation Program (3DEP) bare-earth DEM, read from the 3DEPElevation service at 10 m and averaged to the 30 m grid (downloaded 2026-11-02, U.S. public domain).
• Land use and land cover. ESA WorldCover 2020 (v100), CC BY 4.0. © ESA WorldCover project 2020 / Contains modified Copernicus Sentinel data (2020) processed by ESA WorldCover consortium. The class codes 10 to 90 of the land-use table are WorldCover's.

The other inputs are uniform values set for the example, not outside data: one soil class (class 8 of the soil table), a depth to bedrock of 1.5 m, an LAI of 1, an albedo of 0.25 and an initial soil moisture of 0.1104. The other parameters come from the Stanford case workbook distributed with the MATLAB model.

Figure 1. The two spatial inputs on the 30 m grid. Top: terrain from USGS 3DEP. Bottom: ESA WorldCover 2020 land cover, with the share of each class in the domain. The circle marks Searsville Lake, where the deepest water of the run is.

What this case is meant to show

This case highlights:

• runoff generation under a simple, known forcing;
• the interaction between topography, roughness, and infiltration;
• the spatial organization of routed flood depth, velocity, hazard, and cumulative infiltration;
• long recession behavior after the rainfall pulse ends.

Simulation video

The animation below shows the 30 m simulation. The panels show flood depth, velocity, hazard metric, and cumulative infiltration over a hillshade of the DEM. The still frame is t = 3.5 h, the time of the peak outflow across the domain edge.

Stanford 30 m controlled rainfall simulation: flood depth, velocity, hazard, and cumulative infiltration.

Each panel uses one color scale for the full sequence. The scale is based on the 99th percentile of all saved frames.

Summary results

The simulation saved 97 map frames, one every 15 min. The run summary gives:

Result	Value
Drainage area	156.823 km²
Rain applied	100.00 mm
Runoff coefficient	0.47
Peak outflow across the domain edge	473.69 m³/s at 3.5 h
First peak of that outflow	402.84 m³/s at 75 min, when the rain stops
Maximum flood depth	5.87 m, in the Searsville Lake basin (37.410° N, 122.234° W)
Area that was deeper than 1 m at some time	4.3 km² (2.7% of the domain)
Volume error	-6.45 × 10⁻¹² of the inflow

Every cell on the domain edge lets water leave (perimeter outlet), so the hydrograph is the outflow across the domain edge, not the flow at the creek mouth alone. The flows are its 15 min samples. The first peak, 402.84 m³/s at 75 min, is hillslope runoff leaving along the whole edge. The flow then falls to 110 m³/s at 2 h. After that the creek's flood wave reaches a stretch where San Francisquito Creek runs on the north edge of the domain. The water that overtops the bank there leaves the model, and the outflow rises again to 473.69 m³/s at 3.5 h.

How to run it

The case is in the HydroPol2D MATLAB repository, in Examples/Stanford. In MATLAB, from the root of the repository:

addpath(fullfile(pwd,'Examples','Stanford'))
run_stanford_local_case('Resolution',30,'SimulationMinutes',1440, ...
  'RainfallTimeseriesPath',fullfile('Examples','Stanford','Forcing','Rainfall','Rainfall_Intensity_Website_100mmh_1h_24h.csv'), ...
  'RecordTimeMapsMinutes',15,'RecordTimeHydrographsMinutes',15, ...
  'OutputTag','Stanford_30m_Website_100mmh_1h_24h')

The results go to Examples/Stanford/Outputs/Reruns_CurrentModel/Stanford_30m_Website_100mmh_1h_24h/Modeling_Results: maps of depth, velocity and hazard every 15 min, the hydrograph of the outflow across the domain edge (Tables_CSV/Outlet_Hydrograph_Data_Outlet.csv) and the run summary (Tables_CSV/Summary_Table.csv).

A shorter run of the same storm, 3 h instead of 24 h, starts with run('Examples/Stanford/run_excel.m') and takes about 14 min on a laptop. The README of the repository lists its expected results.