Challilo Dam
Two main things struck me this year as being different about this day’s visit. Firstly, the areas of pine forest that had previously been affected by pine bark beetle were showing a lot more ground cover than previously and the vegetation cover in general was much more prolific. Secondly, the water level in the dam was the lowest that we have seen it, no surprise here really given what we have been told of the rainy season so far.
This year we got to go inside the dam itself and walk a little way along the gallery. It’s much bigger than the other dam galleries I’ve been though. There is some instrumentation to measure seepage through the dam. An interesting snippet that I didn’t know previously was that the dam construction technique used was roller compaction of the concrete.
During the discussion with Mr Reynolds the Chief Engineer the matter of water quality came up. There were a couple of points that I noted. First he said that one of the reasons for the high level of sediment that they had on one occasion was that during a period of high inflow the water was ‘short cutting’ across a bend in the river and as a result it picked up a lot more sediments as well as other woody & vegetation debris. As this was carried in on colder water it was near the bottom of the impoundment and when released through the dam valves it carried the sediment with it. Dam impoundments will of course change the water quality of the water stored from that of the natural flow which under certain conditions impact the downstream ecology as much as the alteration in flow regimes.
Belmopan
Spent quite a bit of time going through the assignments, after we had reached the Climate Change Centre’s offices. There were some clarifications that needed to be made to them. For example, the results of the fieldwork at Monkey River need to be shared among all the groups so that all can write them up and have a good overview of what was done. So the information needs to be shared. Also there was no fieldwork as such on the Macal River at the dams so you cannot include what’s not done. And the Assignment 3 should be about 2000 words.
Whilst at the Center we met with the Deputy Director of Petroleum and Mining and had a very interesting conversation about sand and gravel abstraction in Belize. He has offered to get to us information on previous sand and gravel abstractions from the Bladen and Swasey Rivers. Much of the abstraction in the upper part of the Swasey is done for the Ministry of Works and that therefore there is somewhat less control over what is taken out. It would appear from what he was saying that under his leadership the abstraction regime has tightened up considerably, even though they have a small number of people. They rely on ‘whistle blowing’ as well as unscheduled inspections three times a year. He also said that he would like to collaborate on future field trips in a similar way to what the Hydrology section does at present.
I am somewhat concerned over the deterioration of the water quality samples, we will have to get them to the Laboratory in the morning. Even then I am not sure if we will get any reliable results. This is an aspect we are going to have to look at in the future as we really must get them tested as soon as possible. I read that the University of Belize was (in 2007) setting up a water quality laboratory – we should look into that and see if there is some way in which we could share resources.
Blue Creek Mennonite Community
Aquifers and their water quality, water quality of surface water, water issues within communities and if there is any competition between users in the area. It was mentioned that there were transboundary problems in the upper part of the watershed. Flooding was mentioned as a problem and that the farmers were developing tir own dams to capture run-off which was partly in response to changes in the legislation governing water allocation. The remark was made that the legislation changes would only affect domestic water – to be checked.
Checks including impact on water quality, on the first use of pesticides is done through the Pesticides Control Board. Other than that there is n control of water quantity or quality. The Mennonites said that they reuse a lot of the water that they take out of the Rio Bravo, it is stored in the drainage channels. Salinity levels are vey high.
We were told about a ‘cooperative’ community that does rain-fed rice growing in the upland areas above Blue Creek, these we found including the mill where they bring the grain.
Travelling down to Hill Bank we noticed just before the entrance a centre point irrigation system and it later transpired that the land development was being undertaken by the Mennonite community. One of the reasons we were later told for the buying up of the land by Programme for Belize was to prevent land conversion by the Mennonites to agriculture. They were growing beans and sorghum in the area.
Hill Bank and Programme for Belize Forestry Protected Area.
Not that much of interest in what we did here to water resources. The possibilities are to look at surrounding land use practices and their impact on water resources – development pressures, land conversions especially the difference between that undertaken by Mennonite communities and Metitzo communities in the Orange Walk District. It might also be interesting to think about what impact land conversion to agriculture is having on the recharge and run-off to creeks in the area. In theory if there has been substantial conversion then there should be impacts but quite what they might be would have to be determined.
Some basic subsurface geology and hydrogeology mapping would be required.
The change over to the pine forest areas is quite abrupt. What was also surprising was the dampness of the soil underneath the floor litter even though it had been quite some time since there had been rain.
Bowen & Bowen Brewery
Excellent tour as usual, Mr Lorensa was once again an informative and entertaining guide. More to follow.
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