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Zoom in to level 12+ to see flood zones
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36,121 gauges visible

Community Data

Submit a Field Observation

Share rain gauge readings, flood depth measurements, or site photos from the field. All submissions are reviewed before appearing on the map — your data helps engineers and consultants calibrate flood models.

What are you submitting? *
Rain Gauge Data
Flood Depth Data
Site Photos

Select all that apply.

Location *
Measurements
Files & Photos

Drag & drop files here, or browse

Accepted: CSV, XLSX, PDF, JPG, PNG · Max 20 MB per file

Your Information

Your contact info is used for follow-up questions only and will not be displayed publicly on the map.

CivilIQ · Hydrology & Site Intelligence

CivilIQ

Texas hydrology & site intelligence

We work at the intersection of hydrology, data infrastructure, and open science — building tools that make water data more accessible to engineers, researchers, and the public.

Currently maintaining a consolidated database of 36,000+ rain gauges across Texas and surrounding regions, spanning sources from USGS to Weather Underground.

36K+
Rain gauges
10
Data sources
TX
Primary region
~30yr
Data span

Tools & sources

USGSCoCoRaHS Weather UndergroundLCRA GHCNPython Leaflet.jsGeoJSON

Get in Touch

Let's talk water data.

Questions about the gauge map, collaboration ideas, or just want to connect with our team?

Based in
Texas, USA
Find me online
© 2025 CivilIQ · Texas Hydrology & Site Intelligence

Pick Location on Map

Click anywhere on the map to set coordinates.
Rational Method
Q = C · i · A
A — Drainage Area
What is drainage area?
All the land that drains rainwater to your outlet point. For a backyard it might be your lot. For a culvert it could be hundreds of acres uphill. Use StreamStats above to auto-calculate, or draw/enter manually below.
Don't know your acreage? 1 acre ≈ a football field · 10 acres ≈ a small subdivision block · 100 acres ≈ a large farm
or drop a shapefile
Drop shapefile (.zip) or GeoJSON
Polygon → area calculated automatically · Drawn on map
Use the search bar on the map to find your HUC code, or look it up at mapper.waterdata.usgs.gov
C — Runoff Coefficient

Select land use or type a custom value:

Roofs / Concrete / Asphalt
0.95
Commercial / Business
0.85
Industrial / Institutional
0.70
High-density Residential
0.60
Medium-density Residential
0.45
Low-density Residential
0.30
Parks / Cemeteries / Golf
0.25
Cultivated Agricultural
0.20
Pasture / Grassland
0.15
Forest / Woodland
0.10
What are you designing?

Select what you're building — we'll pick the right storm size. Engineers can set manually below.

Backyard drainage / landscaping
Handles average heavy rain
2-yr
Driveway / parking area
Handles most storms in your lifetime
10-yr
Residential subdivision
Required by most Texas cities
25-yr
Road or culvert crossing
Standard TxDOT requirement
50-yr
Detention pond / near floodplain
FEMA flood insurance standard
100-yr
Dam / critical infrastructure
Catastrophic event planning
500-yr
Tc — Time of Concentration

Tc determines how quickly rain reaches the outlet — it sets the storm duration for your intensity value.

Draw your flow path from the furthest upstream point to your outlet. We measure length and fetch elevations automatically.
or drop a shapefile
Drop flow path shapefile (.zip) or GeoJSON
Polyline → length measured · Polygon → centroid used as flow path
or enter manually
i — Rainfall Intensity (in/hr)
Open full Atlas 14 for this location

⚠️ The Rational Method (Q = CiA) is appropriate for drainage areas up to ~200 acres. For larger watersheds use TR-55 or HEC-HMS. Results should be verified by a licensed engineer.

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