Next steps in Planning, sometimes it works

So having completed Step 1 (see earlier posts) it was on to my first big "water and civil engineering feasibility study". What do you need to plan for a dam?

1. Demand - what's the water for

2. Locations

3  At least one river to put it on

4  Guidance

Repeat Step 1

Step 2 As the Dam was to work in conjunction with other dams it had to be considered as a system, so I was pointed towards a computer terminal (for those that don't know that's a dumb computer linked to a mainframe which was in a large room we were not allowed in.)  We used a programme called HEC3 for dam system analysis which had been "borrowed" from the US, albeit with only a photocopied manual which you can now google for. The hardware requirements for the programme are shown below

Which in modern parlance is probably an iphone but in our case was a lot bigger.  A key part of the manual is describing the punch cards necessary to input into the computer which you would pass through a hatch to the IT department for them to add to the queue and run overnight.  The next day you would come in and find out the cards had been in the wrong order, repeat as necessary.

Step 3 OK Step 2 was slightly more complicated than described above but now I had the required storage, head and outflows. Now a detailed search of maps to find river valleys in the rough location and likely positions for the dam, not too wide, reservoir basins not to shallow (to avoid evaporation losses) and decent founding rock (a introduction to geological maps and a revisiting of my University geology notes).

Having found suitable locations, sketch up dam profiles, consider a variety of dam types (concrete gravity, rockfill, rollcrete etc.)

Step 4 Cost up dam options and prepare recommendation report.

Step 5 Watch report disappear into black hole never to be heard of again

Step 6 continue reminder of year in Planning directorate looking at other dams on the Crocodile River and others and then rotate to the Canal Design Directorate.  The Department used to rotate graduates through planning, design and construction to enable them to understand where projects came from, how they should be designed and, in the construction phase, how they could have been designed better.

Was that the end for the Eerstepoorte Dam on the Groot Marico River?

Some 5 years later, towards the end of my time in Africa I was reading a technical journal one evening (a sad life!) when I came across an article on the Molatedi Dam which happened to be in a narrow gorge at Eestepoort on the Great Marico!  Of course being an engineer I compared my feasibility study with the as built dimensions

Element                                                    Design             Feasibility

Lowest Foundation level:                    RL 931.0m      RL 931.0m

Full Capacity Level                                 RL958.0m       RL959.0m

Non overspill crest Level                      RL963.5m       RL963.5m

Maximum wall heights                           27m                 27m

Overspill length                                      165m               160m

Concrete volume                                 60000m3          63000m3

So - not a bad feasibility study, cannot remember if I got the cost right though.

Lessons Learned

1. Ask questions

2. Listen to the answers

3. Some Projects are actually built

4. Computers get smaller and faster

5. Civil Engineering isn't just concrete and steel design

6. Pictures of your schemes can be found on the internet. Wikipedia isn't always correct:  Molatedi Dam is an earthfill type dam located on the Marico River, near Zeerust, North West, South Africa. It was established in 1986 and serves mainly for irrigation purposes and domestic supply.

8. Rotating through different departments is a good idea as it gives you a much bigger picture view