MELS is a hydraulic design and analysis suite that enables designers to quickly trial several alternative Minimum Energy Loss (MEL) culvert designs, checking for basic structure dimensions, performance under adverse conditions such as high or low flow and sedimentation issues. Full set-out dimensions are given as output along with graphical outputs to facilitate visual checking.

The program MELS is designed for use by engineers in Catchment Management Authorities, Local Government Organisations, and hydraulics engineering consulting practices who are involved in the design of culverts or bridge waterways of virtually any size.

With its user-friendly interface and supporting documentation, MELS is quite easy to use, although some effort will be required to become completely familiar with all the aspects of the design and analysis suite. It is a design tool and, for informed application of the program, users should have a sound background knowledge of open channel hydraulics, including concepts of flow profile calculation. Experience in the design of conventional culverts would be a distinct advantage.

There have been many Minimum Energy Loss structures built in the past, particularly in Queensland and Western Victoria, (in the Stawell region). With a very narrow barrel, MEL structures can be significantly cheaper than a conventional culvert. With their very low energy loss characterisitcs, they are also particularly useful in situations where a water level rise (afflux) is to be avoided. A further feature of an MEL structure, thanks to the smooth streamlining of the outlet fan is the virtual elimination of erosion problems.

The design section of the program solves the complex iterative equations required to compute the shapes of smooth inlet and outlet fans, the bed profiles and energy losses. Other parts of the suite are used to check the design at off-design flows, for sensitivity analysis or with sediment input. With the design reduced to a simple procedure, it becomes very easy to compare essential features, and cost, of an MEL design compared to a conventional culvert design.

Although very simple design spreadsheets have been proposed in the past, the unique MELS suite of programs correctly solves the complex iterative equations required to compute the shapes of spiral inlet and outlet fans and matching bed profiles. Friction losses are correctly computed as a function of varying velocity throughout the structure and exit loss is also accounted for. Alternative hand methods, with the use of flow nets and or very simple wall shapes are thus avoided. Other parts of the suite are used to check the design at off-design flows, for sensitivity analysis or with sediment input. With the design reduced to a simple procedure, it becomes very easy to compare essential features, and cost, of an MEL design compared to a conventional culvert design.