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Thanks for the quick reply! Is there an exportable hydrograph within HydroCAD that would have percentage of total flow vs. time, so that I could just apply my known peak multiplier to the Y axis?

I have a project that involves a dam with a 130 square mile watershed. Part of the project is to de-water the impoundment. I am trying to model what happens when a storm event hits during these draw downs (empty unit, partially full, full). I have my stage-storage table, a user-defined outlet...

It's a combination of uses. In most of our projects, there's a lot of active water level management. Part of what I'm looking at is what the drawdown times (from flat pool) are for various gate positions and then what would happen if a storm hits when the gate is at a particular postion.

Is there a way within HydroCAD to model a partially open slide gate on the front of a round pipe without going into custom orifice development? My situation is a fixed crest dam with a bypass pipe that has a canal gate on it. I'd like to be able to model the flows through the pipe that come...

Yup, river comes up and I need to fill my wetland at about the same rate. I'll just go the spreadsheet route. I don't know within the computational engine of HydroCAD if it would take much tweaking to allow a link to serve as an input, but it would be handy for our large river and coastal...

I'm trying to size a broad-crested spillway for flooding, so the river would be an inflow. Elevation vs. time would be ideal for my situation, but I remember from earlier attempts at some tidal modeling that the link tailwater has a one way flow aspect and can't be used for filling. Flow vs...

I am trying to model a river flooding into my project. I have the gage data for the river's elevation vs. time, but I'm having trouble trying to set that as a flow input for my unit. I'm looking to set either a subcatchment or pond that has a linear increase in elevation with respect to time...

The parabolic weir is the low flow condition in the pipe (spilling out over the arc of the bottom of the pipe).

The culvert is round, so I didn't set any extra parameters. I know HydroCAD auto-checks for a lot of things, so I didn't want to override any of that.

At very low flow depths, I am assuming that it won't fall under any of the culvert equations. That should leave me with weir flow or open channel as my options. I couldn't find in the documentation what equation HydroCAD used for a parabolic weir. If I have that equation, then I can check the...

I have a situation where I need to keep a pump fed with water that is flowing through a pipe with a negative slope. I set up a pond node with the culvert and an arbitrary storage area extending beyond my ranges of concern. When I check the discharge at low head levels (below the midpoint of...

So, I can create a backfill situation by looping two pond nodes (assigning storage values to both), but it's going to route from the starting elevation (and any rain events) only - i.e. no cyclical components. The other option is to route a pond into a tide link, which will allow for cyclical...

I have a situation where I have a pond outletting into the ocean. A portion of the tidal influence will be above the normal water surface of the pond. I am interested in determining the effects on the pond due to ocean water, independent of rain events. My current model is a detention pond...

My wall has a relatively toe, so I haven't looked at the passive resistance for overturning. The only information I found on sliding was to take the weight of the structure and the vertical earth pressure and multiply by the tangent of the angle of internal friction. In my case this is way...

I have a reviewer that won't accept HydroCAD. What I'm trying to show is the effects of a change in pipe for a dam outlet. He wants a description of existing and proposed flows for all possible iterations. It's easy enough to toss the required information into a pond node and create a...

I have a few general geotechnical questions: In designing a retaining wall, there often needs to be a key to resist sliding. The soil in front of the key has to go into compression. Is there a set distance in front of the key (the area in compression) where the compression occurs? If so, how...

I have been asked to get up to speed on dam breach analysis for permitting. Most of the work is low hazard, relatively short (under 10' high) dams. I don't have any real background in HMS or RAS. My general understanding is that HMS provides the hydrology and hydrographs, while RAS provides...

The project is an attempt to raise the groundwater level in a given area. I need to show that the surface water levels will not be any different pre-project vs. post-project. Permanent pool levels are easy enough to show, but I also have to prove the flows during storms aren't going to be a...

If I have a broad-crested weir where the breadth is 15' or more, the weir coefficients are almost constant at 2.63. The broad-crested weir device does not have the rise function to "turn it off" once the elevation of the next flow control has been met. So, since the sharp-crested vee/trap...

As far as the generic CN's for 1/2 acre lots, I had an engineer that buggied off all of the impervious areas in a 1/4 acre lot subdivision. The number was right on target with the NRCS assumed percentages of impervious.