About CrestWatch

CrestWatch turns the government's river forecasts, written for engineers, into one plain sentence about your own house: when the water is coming, how high, and whether it reaches your door, in a district that once stayed flooded for six months while the forecasts sat unread.

The problem

In 1927 the levee broke at Mounds Landing near Greenville and put much of our district under water. It was the most destructive river flood in American history. In 2019, the Yazoo backwater flood kept over half a million acres of the south Delta underwater for about six months. In August 2022 the Pearl River flooded Jackson and knocked out the city's water plant (CNN). The 2019 and 2022 floods were forecast days ahead, on government pages written for engineers.

What CrestWatch does

  1. 📡

    Check the gauges

    River gauges and the official crest forecasts, straight from USGS and NOAA.

  2. 📐

    Compare to your ground

    Your address becomes a height. The forecast becomes a water level. Then we subtract.

  3. 🗣

    Say it in one sentence

    When the water is coming, how high, and whether it reaches your door.

What it can't do

CrestWatch predicts river flooding, the slow kind our district gets, with days of warning. It can't predict flash floods from sudden rain. Its numbers are estimates from public elevation data, not a survey of your property. When it's too close to call, it says so. It only checks the river while it's open, and it doesn't send alerts. Keep the emergency alerts on your phone turned on. CrestWatch doesn't count levees or floodwalls. A place behind one can stay dry when the numbers say water would reach it, and a levee can also fail.

Privacy

Your saved places live only in this browser. CrestWatch also keeps its last answer here, to show for up to 12 hours if your signal drops. To look an address up, CrestWatch's server sends it to public map services: the US Census first, then OpenStreetMap (Nominatim) or Open-Meteo if the Census can't find it. Then it asks USGS and the Weather Service about that spot. Each time it checks, your browser sends your places to CrestWatch's server for that check. The server doesn't save them. It keeps lookups in short-term memory for up to a day so repeat checks are fast, and counts checks from each internet connection for an hour to stop abuse. A watch link you share has your places inside it. No accounts, no database, no tracking, no ads.

How it was built

An AI coding tool, Claude Code by Anthropic, wrote almost all of this app's code, and we say so openly. The app itself uses no AI, only public data and arithmetic. It runs on Next.js and TypeScript with free public data from USGS, NOAA, and the Census. Address search also uses OpenStreetMap's Nominatim and Open-Meteo's place search, which is based on GeoNames. See AI_DISCLOSURE.md.

Who we are

Built by students in Mississippi's Second Congressional District. A Congressional App Challenge 2026 entry.