Hi every one here
I have a task to analyse slopes and provide a suitable water flow proposal. Any one knows how to prepare a flood analysis map here?
thank you
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I have used Landserf to create ridge, peak, channel with flow analysis from DEM's created from LiDAR data for bioengineering stream bank retention. http://www.staff.city.ac.uk/~jwo/landserf/landserf230/
QGIS and GRASS also have very good capabilities in this area, but I have never used them for this specific purpose. https://www.qgis.org/
Are you asked to collect the data for analysis, or complete analysis on data that has already been collected?
Hello, Mashaka. I'm a licensed civil engineer in Colorado, Texas and Hawaii. About a third of my 35+ year career has been flood related issues.
You didn't mention what jurisdiction, or part of the world you are working in, but local laws often dictate who can do what. As mentioned elsewhere in replies to this post, flood flow, and flood plain analysis is usually the domain of a civil, hydrologic, hydraulic or water resource engineer.
As for software tools, there a number of good choices, but it completely depends on what the application is. Additionally, experience in knowing what are valid inputs is absolutely critical. The "cookbook" approaches built into many of today's CAD platforms must be used with a great deal of caution. As with all software tools, the statement still applies: "garbage in, garbage out."
It sounds like you need to find a water resource professional in your area to assist you, or to do the work.
Best regards,
- Paul
Paul makes some really good points. There is drainage design, then there is drainage design! My first experience with it was when it meant getting the water to the ocean by the most direct & economical route. Then along came FEMA & DHEC & we are now dealing with such things as "retention & detention" & everything got a lot more complicated & technical.
Dear masahaka,
Since you have to do flood analyse so at first you have to do survey for spot level and detailing for main structure such as bridge,culvert, some big land mark(govt building), Water body etc.Since it is vast area you can purchase google earth site for particular surveyed place.And you purchase software(Auto plotters google earth which is indian company) to extract the data from google earth.From google earth you can not get water bodys below surface from water level.For that case you have to do hydrography survey by echo sounder and dgps instrument.After getting all data then you create contour by software (Autoplotter).And find out the ridge line.According to contour and topograhy you decide from which side is suitable for passing the water to canal,river or sea.For making canal or drain give 1:100 slope to pass the water for flood control
Autodesk Civil 3D or Carlson Civil Suite ought to suit your needs
Excellent suggestion, Kevin. We use Carlson Hydrology and Hydrocad together...so simple for an excellent solution
I worked briefly for the SC State DNR as a surveyor out of the engineering office. I would use what works for you. Different strokes for different folks. I had the Carlson full Civil Suite. Mr. Carlson came to our office & I talked to him in person. Personally, I don't like his software. Some of my peers do like it. A lot depends on what you are accustomed to using. Nobody gives me anything, I can't send a bill to the taxpayers. All I get from the government is a tax bill.
Software is a tool, it is not a replacement for knowing what you are doing. That is normally the job of a civil engineer, which I am not. I have, in my younger days, done a lot of drainage design but only under the supervision of a licensed Civil Engineer. You have to define the watershead, a lot of parameters like time of concentration, run off coefficients and such. I stick to surveying & leave the engineering to the engineers. Actually, I'm getting rather picky about the surveying jobs I will attempt.
It's a big world out there, Charlie. What professional regulation laws apply in your State, may not apply in another State (e.g., if I'm not mistaken -- it's been a very long time since I've done any work there -- but, in Georgia, a candidate for licensure as a surveyor MUST have hydrology coursework / training). Who knows how the rules & reg's in some State compare to those in Tanzania.