Tools built for professional hydrology

Time of concentration using multiple published approaches including Kirpich, Bransby-Williams, SCS lag, Kerby, Giandotti, and helpers tied to flowpaths.

Delineate catchments from MERIT-Hydro and related DEM sources with stream ordering, longest flowpath extraction, and GIS export.

Longitudinal watercourse profiles with elevation sampling along streams — document slopes and falls for hydraulic and geomorph studies.

Depth–duration–frequency (DDF) estimates and IDF-style curves from regional models and international datasets, plus user data import where needed.

Explore and download historical daily rainfall records for South African stations and selected international sources.

Synthetic design hyetographs including alternating block, SCS/NRCS distributions, Huff-style partitions, and large regional pattern libraries.

Areal reduction factors for South African design rainfall using published regional guidance, catchment polygons, and depth–duration context.

Probability rainfall multiplier workflows for scaling South African design rainfall inputs where TR102 / RLMA-style adjustments apply.

Peak discharge from the rational formula Q = CiA with runoff coefficient guidance, design rainfall integration, and multi-return-period tables.

Graphical peak discharge method following USDA NRCS TR-55 for estimating post-development flows and comparing pre/post scenarios.

Build synthetic unit and design hydrographs including SCS dimensionless UH, triangular hydrographs, and custom peak/volume targets.

Open-channel hydraulics with Manning's equation: trapezoidal, rectangular, circular, and custom sections with normal/critical depth and rating curves.

Stable lining selection using tractive-force concepts consistent with HEC-15 for vegetated, riprap, and articulated-block systems.

Culvert hydraulics with inlet and outlet control checks, headwater–discharge performance curves, and multi-barrel configurations.

Stormwater detention routing with Modified Puls level-pool routing, multi-stage outlets, and target release workflows.

Head–discharge relationships for broad- and sharp-crested weirs with submergence checks and practical sizing feedback.

Gradually varied flow profiles using the direct step method with M1, M2, S1, S2 classification support along prismatic channels.

Fit and compare frequency distributions (LP3, GEV, Gumbel, Normal, and more) using method of moments, L-moments, and MLE with best-fit ranking.

Regional frequency analysis using the index-flood approach — combine site and regional information for robust estimates where data is sparse.

Quantile regression techniques for flood estimation at ungauged sites using catchment attributes and regionalized predictors.

Locate streamflow gauges near your study site, filter by agency and record length, and jump into analysis workflows.

Probable maximum precipitation estimates for dam safety and extreme-event design, including HRU-style classification workflows.

Regional maximum flood estimates for extreme-event checks using envelope-style approaches applied in South African practice.

Dam safety study workflows including classification context, extreme rainfall inputs, and routing concepts aligned with South African dam practice.

Map-led catchment studies: delineate a catchment, run multiple flood estimation methods, and export design-grade Word, Excel, and GIS outputs.