Introduction

Overview

Flood App is a RESTful web service that integrates with the Fora.ai platform to support participatory watershed modeling. Built on Landlab, the service performs watershed-scale simulations of surface runoff and soil infiltration based on user-defined landscape conditions and mitigation interventions.

Community users interact through the Fora.ai platform to discuss, collaborate, and design modeling scenarios that incorporate mitigation measures such as berms and mulch. Fora.ai sends GeoJSON-based map data to Flood App through a REST API, where the inputs are processed and translated into physics-based simulations using Landlab components. Simulations are executed asynchronously, and the resulting outputs are returned to Fora.ai for visualization, scenario comparison, and decision support.

The system is designed to facilitate participatory modeling, enabling stakeholders to evaluate alternative mitigation strategies, assess flood impacts, and support watershed management decisions.

Flood App workflow diagram

Intervention Types

Three intervention types can be applied to landscape cells via the GeoJSON input.

Type

Description

berm_low

Raises cell elevation by 1 m and adjusts hydraulic conductivity and Manning’s roughness.

berm_high

Raises cell elevation by 2 m and adjusts hydraulic conductivity and Manning’s roughness.

mulch

Modifies hydraulic conductivity and Manning’s roughness; no change to terrain elevation.

Input Example

An example request JSON file can be found in test_request_geojson_valid.json.

Output Files

File

Contents

surface_water_depth_<t>.json

Per-timestep water depth grid

infiltration_<t>.json

Per-timestep infiltration depth grid

max_water_depth.asc

Maximum water depth (ESRI ASCII)

max_surface_water_depth_final.json

Maximum water depth grid (JSON)

watershed_elevation.json

Elevation grid of delineated watershed

outlet_discharge.csv

Time series of outlet discharge

cum_result_test.txt

Cumulative discharge percentage

infil_result.txt

Cumulative infiltration percentage

evaluation_results.txt

Damage cost, flooded area, investment NPV