How do you perform a flow analysis from point clouds? Generate a Tin? A DTM? Extract vectors and build a surface from it? What key factors you take into account? And what is the most useful output?
As a surveyour, who has little to none experience in the topic, I'm curious, how hydrology engineers utilise the point clouds and how does the outcome looks?
After a few dry years we finally got a good snowpack up in northern Alberta. Cost me a level logger but we got good ADCP data and we will get level from survey till it recedes. Feels good finally see peak flows.
Hello, I'm a undergraduate student in a Watershed Hydrology course where we are using Hec-Hms for our term project. I finally got it to run a simulation but only some subbasins will produce a hydrograph. The other subbasins will throw out a "Error : Error opening editor. Contact HEC for assistance." Afterward they will let you open the results for them but will not produce any of the result files except for the precipitation and precipitation loss graph (while missing the hydrograph) and a snowmelt graph with SWE, Air Temperature, and Precipitation. I'd like anyone who has any free time to take a look at it and let me know what obvious fixes I could make. (I can send screen shots or send my files to others if need be)
Just finished my math undergrad with a roughly 3.9 gpa and want to do a Hydrogeology masters (both parents are hydrogeologists haha) Is this feasible? I have no coursework in earth sciences (mostly just math courses plus a few general science from first year). I’m in Canada.
Good day!
I am a 4th-year Civil Engineering student conducting a study titled “Flood Vulnerability Assessment of the Guadalupe River Basin Using the Analytic Hierarchy Process–Multi-Criteria Decision Analysis (AHP-MCDA)”.
We would like to request your assistance in answering a short questionnaire to provide expert input for our AHP-MCDA analysis. We are aiming to gather at least five (5) experts/respondents with backgrounds in hydrology, urban planning, disaster risk management, and GIS-based flood risk assessment.
Your insights would greatly help improve the accuracy of our study. All responses will be used for academic purposes only, with proper acknowledgment.
Thank you very much for your time.
Hello!
I’m working on a river modeling project in HEC-RAS and I'm still a beginner and had a couple of practical workflow questions:
What’s the most efficient and accurate way to draw cross-sections perpendicular to the river channel?
- I’m currently using GIS (QGIS) to digitize them, but ensuring true perpendicular alignment along a meandering channel is tricky.
- Are there recommended tools, plugins, or workflows (centerline-based, stationing methods, or automated XS generation) that work reliably?
How do you accurately determine bank stations in a cross-section profile?
- Do you rely purely on DEM breaks in slope, field survey data, or visual judgment?
- Any best practices to distinguish main channel vs overbank areas, especially in flat or subtle terrain?
Would appreciate any tips, workflows, or common mistakes to avoid—especially from people working with GIS + HEC-RAS integration.
Thanks!
The two I've seen most often, in junior engineers and not-so-junior engineers alike:
Applying Kirpich to urban / mixed watersheds. Kirpich (1940) was calibrated on rural Tennessee farmland with 3-10% slopes and single flow paths. Plug it into a 200-acre suburban subdivision with mixed land cover and it'll under-predict Tc by 30-60%, which means over-predicting the rainfall intensity, which means over-sizing every pipe in the system.
Confusing NRCS lag T_L with Tc. T_L is 60% of Tc by NRCS's own documentation (NEH-630 Ch. 15), but a startling number of spreadsheets out there carry the lag value through as if it were Tc and end up sizing for the wrong storm duration on the IDF curve.
I put together a one-page comparison of every common method (Kirpich, NRCS Lag, TR-55 segmental, FAA, Kerby/Hathaway), with their validity ranges, side-by-side equations in US and SI units, and the common-mistakes list: https://pe-calc.com/cheat-sheets/time-of-concentration-methods.html?utm\_source=reddit&utm\_medium=social&utm\_campaign=hydrology\_tc
And a worked end-to-end example showing TR-55 segmental on a 12-acre rural watershed (sheet flow + shallow concentrated + channel flow, then Rational Method, then HDS-5 culvert, then Manning's outlet velocity check): https://pe-calc.com/educational/culvert-sizing-worked-example.html?utm\_source=reddit&utm\_medium=social&utm\_campaign=hydrology\_tc
Genuinely curious — what's the misapplication YOU see most? My default for anything urban or mixed is TR-55 segmental, Kirpich-only for true rural single-flow-path watersheds. Anyone using kinematic-wave methods on small watersheds in production work, or is it always TR-20 / HEC-HMS once you outgrow Tc-driven design?
Is a tracer test a viable and effective investigation tool for identifying and confirming a wastewater treatment plant (WWTP) as the source of microbial contamination in a drinking water production well, when the suspected source is located approximately 3 km upgradient from the receptor? The aquifer is karstic, characterized by preferential flow pathways and fracture-dominated transport.
The perforated casing sections are installed at depths ranging from approximately 543 to 683 m below ground surface, representing the primary production interval. The total drilled depth of the well reaches approximately 714 m. These formations are predominantly limestone to dolomitic in character, with abundant karst voids and fracture networks encountered throughout drilling, as evidenced by the numerous total circulation losses recorded during the drilling campaign.
I'm asking because I'm concerned about the traces' dilution in the aquifer. I'd appreciate any advice or insight.
