A complete hydrology & hydraulics studio, in your browser.
Delta Hydro Studio links catchment, rainfall, runoff, and hydraulics into one workflow — with transparent methodology and export-grade tables.
-33.9321, 18.8602 · WGS84
Run the numbers now
The same engines as Delta Hydro Studio, in SI or US customary units, each with a method guide and worked example. Saving and exports open with Studio accounts soon; join the waiting list to be told first.
Rational method calculator
Peak flow from Q = CiA, with a runoff coefficient lookup and an area-weighted C for mixed land use.
Open calculator RunoffTR-55 calculator
Runoff depth and peak discharge by the NRCS graphical method, with a curve number lookup and area-weighted CN.
Open calculator RunoffUnit hydrograph calculator
SCS, Snyder, Clark, gamma and triangular unit hydrographs, with the ordinates and the runoff volume.
Open calculator Frequency & dataFlood frequency analysis
Fit LP3, GEV and Gumbel to annual maxima by L-moments or moments, with outlier and trend tests.
Open calculator RainfallDesign storm generator
Hyetographs from SCS Type I to III, Huff, Chicago and alternating block patterns, from a depth or an IDF curve.
Open calculator CatchmentTime of concentration calculator
Kirpich, NRCS lag, FAA, Kerby and USBR side by side, or the sheet, shallow and channel flow segments.
Open calculator HydraulicsManning's equation calculator
Normal and critical depth, velocity and Froude number for trapezoidal, rectangular, triangular and pipe sections.
Open calculator HydraulicsChannel lining calculator
Permissible shear check by FHWA HEC-15 for riprap, gabions, grass and erosion control mats, with the normal depth.
Open calculator HydraulicsCulvert calculator
Headwater under inlet and outlet control by FHWA HDS-5, with the performance curve and road overtopping.
Open calculator HydraulicsRiprap sizing calculator
Stone size, FHWA gradation class and layer thickness for banks, piers, abutments and culvert outlets.
Open calculator HydraulicsWeir flow calculator
Head or discharge for broad-crested, sharp-crested, V-notch, Cipolletti and ogee weirs, with the rating curve.
Open calculator HydraulicsGradually varied flow
Backwater and drawdown profiles by the direct or standard step method, classified M1 to A3.
Open calculatorBuilt for professional practice
Everything in one cloud workspace — not a patchwork of spreadsheets and single-user GIS scripts.
A complete H&H studio
Catchment, rainfall, runoff, and hydraulics tools in one place — plus frequency analysis and safety workflows when you need them.
Cloud-native — no installs
Run professional hydrology and hydraulics in the browser. Share consistent inputs and outputs across your team.
Design-grade exports
Word, Excel, and GIS outputs structured for deliverables — no copy-paste report assembly.
One dashboard for the whole study
Stop stitching together maps, spreadsheets, screenshots, and “final_final” folders. Delta Hydro Studio is built as a studio: projects keep context, workflows chain tools with consistent defaults, and documentation stays attached to the work.
Projects
Keep studies, assumptions, and exports together so you can revisit, duplicate, and defend decisions months later.
Workflows
Run linked steps with consistent defaults — from catchment context through rainfall, runoff, hydraulics, and reporting.
Team sharing
Share a workspace instead of emailing spreadsheets. Align on inputs, credits, and deliverables with clear ownership.
Reference library
Keep methodology notes, citations, and supporting context alongside the model — reviewers see the “why”, not just the number.
One dashboard
Replace the fragmented toolchain: maps, tables, charts, exports, and QA trails live in one professional workspace.
Custom engineering & integrations
Need bespoke software, QGIS plugins, H&H stack integrations, or dashboards for your agency? We build alongside Delta Hydro Studio. For traditional consulting studies, our practice lives at deltahydro.co.za.
View servicesOne studio, the full H&H chain
Organised the same way you work: catchment → rainfall → runoff → hydraulics, plus frequency analysis, safety, and end-to-end workflows.
Catchment
Delineation, flowpaths, and profiles to anchor everything else.
Browse toolsRainfall
IDF/DDF, design storms, and area reductions for consistent inputs.
Browse toolsRunoff
Peak flow and hydrograph tools to translate rainfall into discharge.
Browse toolsHydraulics
Channels, culverts, detention, weirs, and gradually varied profiles.
Browse toolsFrequency & data
Gauge discovery and frequency methods for data-driven design.
Browse toolsSafety
Extreme precipitation and safety workflows for high-consequence assets.
Browse toolsWorkflows
End-to-end hubs that run multiple steps for one study.
Browse toolsTool suite
Scroll the full lineup — every tile links to a dedicated landing page.
Rational Method Calculator
Peak discharge from the rational formula Q = CiA with runoff coefficient guidance, design rainfall integration, and multi-return-period tables.
TR-55 Peak Discharge Calculator
Graphical peak discharge method following USDA NRCS TR-55 for estimating post-development flows and comparing pre/post scenarios.
Hydrograph Generator
Build synthetic unit and design hydrographs including SCS dimensionless UH, triangular hydrographs, and custom peak/volume targets.
Flood Frequency Analysis
Fit and compare frequency distributions (LP3, GEV, Gumbel, Normal, and more) using method of moments, L-moments, and MLE with best-fit ranking.
Index Flood Method
Regional frequency analysis using the index-flood approach — combine site and regional information for robust estimates where data is sparse.
PMP Calculator
Probable maximum precipitation estimates for dam safety and extreme-event design, including HRU-style classification workflows.
RMF Calculator
Regional maximum flood estimates for extreme-event checks using envelope-style approaches applied in South African practice.
Design Flood Estimation
Map-led catchment studies: delineate a catchment, run multiple flood estimation methods, and export design-grade Word, Excel, and GIS outputs.
QRT Calculator
Quantile regression techniques for flood estimation at ungauged sites using catchment attributes and regionalized predictors.
Design Rainfall
Depth–duration–frequency (DDF) estimates and IDF-style curves from regional models and international datasets, plus user data import where needed.
Daily Rainfall Statistics
Explore and quality-check historical daily rainfall records for South African stations and selected international sources.
Design Storm Generator
Synthetic design hyetographs including alternating block, SCS/NRCS distributions, Huff-style partitions, and large regional pattern libraries.
ARF Calculator
Areal reduction factors for South African design rainfall using published regional guidance, catchment polygons, and depth–duration context.
Tc Calculator
Time of concentration by Kirpich, NRCS lag, FAA, Kerby and the USBR equation side by side, or by the FHWA sheet, shallow and channel flow segments.
PRM Calculator
The Probabilistic Rational Method of Calitz & Smithers (2020): regionally calibrated runoff coefficients for design floods at ungauged South African sites.
Channel Analysis
Open-channel hydraulics with Manning's equation: trapezoidal, rectangular, circular, and custom sections with normal/critical depth and rating curves.
Channel Lining
Stable lining selection using tractive-force concepts consistent with HEC-15 for vegetated, riprap, and articulated-block systems.
Culvert Designer
Culvert hydraulics with inlet and outlet control checks, headwater–discharge performance curves, and multi-barrel configurations — plus a sizing assistant that ranks commercial barrel sizes against your headwater, velocity and cover constraints.
Detention Basin Designer
Stormwater detention routing with Modified Puls level-pool routing, multi-stage outlets, and target release workflows.
Riprap Design
Size protective stone for channel banks, bridge piers and abutments, spurs, culvert outlet aprons, open-bottom culverts and wave-exposed slopes — FHWA HEC-23 and HEC-14, matched to standard FHWA gradation classes.
Weir Analysis
Head–discharge relationships for broad- and sharp-crested weirs with submergence checks and practical sizing feedback.
GVF Profiles
Gradually varied flow profiles using the direct step method with M1, M2, S1, S2 classification support along prismatic channels.
Watershed Delineation
Delineate catchments from MERIT-Hydro and related DEM sources with stream ordering, longest flowpath extraction, and GIS export.
Watercourse Profile
Longitudinal watercourse profiles with elevation sampling along streams — document slopes and falls for hydraulic and geomorph studies.
Stream Gauge Finder
Locate streamflow gauges near your study site in South Africa (DWS), the United States (USGS) or Australia (BoM), filter by record length and status, and send annual peaks to flood frequency analysis.
Dam Safety Evaluation
Dam safety study workflows including classification context, extreme rainfall inputs, and routing concepts aligned with South African dam practice.
From map click to Word report
Four steps your reviewers can follow — with the audit trail they expect.
Define the site context
Drop a pin, trace a reach, or upload a boundary — the map stays connected across tools.
Run the linked steps
Catchment → rainfall → runoff → hydraulics, with guided inputs and repeatable defaults.
QA with transparency
Charts, intermediate tables, and methodology notes stay visible for peer review.
Export deliverables
Generate structured tables and exports your CAD/GIS and report packs can consume.
Who uses Delta Hydro Studio?
Consulting engineers
Design-grade exports, multi-method studies, and reviewer-friendly documentation.
Read use case →Property developers
Screening hydrology for layouts, stormwater and due diligence, with every input on record for the reviewer.
Read use case →Mining & water management
Extreme events, detention, and hydraulics workflows in one workspace.
Read use case →Municipalities
Transparent methods your team can repeat and audit across projects.
Read use case →Students & academics
Teach reproducible methods with transparent parameters and exportable coursework packs.
Read use case →Government & DWS context
Documentation-first workflows for methods aligned with national guidance.
Read use case →Why teams leave spreadsheets behind
The comparison pages cover review trails, collaboration, standards coverage and where desktop GIS still wins, so you can choose the right tool for each job.
Explore comparisonsSimple credit-based pricing
Stream (free), River (Pro), and Delta (Team) — with global checkout through Paddle.
See full pricing →Frequently asked questions
Is Delta Hydro Studio only for South Africa? +
Do I install desktop GIS or HEC-RAS to use it? +
What does “Start free” include? +
Where is documentation? +
How does billing work? +
Can teams share credits? +
Book a 30-minute demo
Prefer to see the product live before you sign up? Grab a slot — we will focus on flood, hydraulics, or rainfall workflows based on what you select in the booking form.
Start free today
No credit card required to explore. Enterprise rollout? Use the calendar above or email sales.