What are the different approaches to including smaller non-regional detention ponds in your hydrology models?
Typically, if I am doing pre and post analysis, I take the more conservative approach of assuming a pre-developed CN (for NRCS) or pre-developed impervious cover (Clark) when...
Does any have any insight and, more preferably, reading / research material discussing the difference between the two methods? Pros & Cons I should say.
Thanks!
Flow Regime: Sub-critical & open surface flow
In a scenario where one needs to do backwater calculations for a channel / culvert in subcritical flow, is assuming normal depth as the US water level acceptable? At some point the backwater calculations will converge to normal depth, but I've never...
Is anyone familiar with this HSG Soil Type, "URLX - Urban Land". I was recently pulling HSG maps from the NRCS website and there was a large residential development with this soil type that matched the boundaries of the development. Looks like pre-developed HSG soils were type B at one point...
What are the limitations of the NRCS Lag method for determining Tc? I know there is a range for the CNs used (50 to 95) but are there any risks to using this method with very small watersheds or using this Tc in the Rational Method?
I am preparing an additional section for a drainage manual that includes supplemental criteria. I would like to use images from the NRCS NEH-630 and possibly an example that they have provided. However, I am not sure on the copy right status of that document. Does any one know?
I do not see any...
I am doing a mitigation study for a proposed development that will be outfalling into a creek. Using the SCS method to developed hydrographs for the creek and the development, I am trying to prove that the new development will not create an increase in peak flow for the creek due to the storms...
I am doing a feasibility model in WaterCAD for water service to a new residential development. My firm's SOP for fireflow is 1500 gpm per fire hydrant using two fire hydrants at the same time (totaling 3,000 gpm) for two hours while maintaining a 20 psi pressure. That standard has been passed...
When doing partially full analysis on closed conduits, if a pipe is surpasses full flow capacity do you switch over to 100% capacity analysis or do you continue analyzing it under partial flow to 93% capacity (real max pipe capacity)?
hypothetical example:
I have 3 pipes with a capacity of 10...
