
Hydrologic Design & Analysis Assistant
Accelerate hydrologic modeling, stormwater design calculations, and water balance analysis
What You Can Do
You can rapidly perform peak discharge calculations using rational method, NRCS, and SCS approaches; size stormwater detention and retention basins with geometry verification; analyze rainfall frequency data and storm events; develop water balance spreadsheets for supply planning; and document hydrologic assumptions with full calculation verification. Claude cross-checks unit conversions, interpretation of USGS/NOAA data, and detention basin orifice calculations to accelerate your design workflow.
Features
Applies rational method, NRCS, and SCS methods with automatic coefficient and runoff calculations for your site conditions
Sizes detention/retention basins and verifies orifice flow rates, storage volumes, and outlet configurations
Develops supply-demand spreadsheets, infiltration assessments, and drought or flood scenario modeling
Analyzes storm frequency, intensity-duration-frequency (IDF) curves, and appropriate return periods from NOAA/USGS sources
Generates design report narratives with CN values, imperviousness ratios, time of concentration, and antecedent moisture conditions
Catches calculation errors, verifies consistent unit systems, and checks intermediate results against professional standards
Helps structure stormwater pollution prevention plans with erosion control sizing tied to runoff volumes
Example Output
Example 1: Peak Discharge Calculation
Input: 2-acre commercial site, 85% impervious, 10-year storm, urban area
Output: Using Rational Method (Q = CiA), Claude calculates:
- Runoff coefficient (C) = 0.72 (weighted for 85% imperviousness)
- Time of concentration = 8 minutes
- Rainfall intensity (i) = 4.2 in/hr (from local IDF curve)
- Peak discharge = 0.72 × 4.2 × 2 = 6.05 cfs
- Recommendation: Size inlet/outlet for 6.5 cfs minimum
Example 2: Detention Basin Sizing
Input: Predevelopment runoff 1.2 cfs, postdevelopment 8.5 cfs, storm duration 30 min
Output: Claude designs basin geometry:
- Required storage volume = 15,200 cubic feet
- Basin dimensions: 120 ft × 130 ft × 1 ft (adjustable depth)
- Outlet orifice: 4-inch diameter (Q = 2.1 cfs at full pool)
- Drawdown time: 4.5 hours ✓ Meets 24-hr minimum standard
Example 3: Water Balance Summary
Output table showing annual supply (municipal + rainfall), demand (irrigation + indoor + cooling), and seasonal surplus/deficit for 5-year drought scenario with recommendations for storage sizing.
What's Included
- SKILL.md: Complete skill configuration and usage guidelines
- Rational Method Workflow: Step-by-step calculation template for peak discharge using C, i, and A inputs
- Basin Sizing Checklist: Geometry verification, outlet orifice design, and drawdown time validation checklist
- Water Balance Template: Monthly supply/demand spreadsheet structure for supply planning and drought analysis
- Hydrologic Assumptions Documentation: Design report boilerplate with CN values, imperviousness, and land cover justifications
- USGS/NOAA Data Interpretation Guide: How to extract rainfall frequency, streamflow, and infiltration data for Claude analysis
Who It's For
- Civil engineers specializing in water resources design and stormwater management
- Hydrologic consultants performing basin studies and flood risk assessments
- Site development engineers designing drainage systems for commercial and residential projects
- Municipal engineers managing stormwater infrastructure and SWPPP compliance
- Landscape architects integrating water balance and sustainable drainage into site plans
Best For
- Rainfall-runoff calculations for design storms of specified return periods
- Detention and retention basin sizing with geometry and outlet verification
- Water supply-demand balancing and drought scenario modeling
- Storm event analysis and peak discharge forecasting
- Hydrologic assumption documentation and calculation verification for design reports
- Stormwater quality and quantity plan development
- USGS and NOAA data interpretation for local hydrology







