All across Africa there are infestations of aquatic weeds clogging the waterways, and sucking the land dry. Typha, Phragmites, water hyacinth and others are using up the water that the people need. They are also blocking drainage, and so causing flooding. They are also breeding grounds for many pests and diseases. Their clearance and control would relieve many troubles. But the reason that these plants are out of control is their resilience.
Their control is a never-ending process, something that can only be sustained at a “real” profit – one that is generated economically, not politically. Fortunately, at least with Typha, there are profits to be had in food, in fuel and in fiber. When grown in clean water and soil, Typha is a champion food producer. What isn’t fit for human consumption can be brewed into ethanol or charred and briquetted into charcoal.
All of the aquatic weeds have the useful/annoying habit of collecting pollutants, so not just any can be eaten. Phragmites has the same fuel uses, but has never been used as a staple food. Water Hyacinth and water lettuce and some of the others have been used successfully as mulch, and as a biomass source for methane production.
The quantities involved are astonishing. There appears to be enough Typha Australis in the Lake Chad basin to feed the entire population of Africa (where it all fit for consumption and harvestable). Picture my horror at a picture of a dozen starving refugees hiding in a Typha stand that would feed and clothe a small town. These people are starving in the midst of plenty. And, unused and unchecked, that cornucopia of food is killing them with thirst.
Typha is a desiccation machine. The infestation in the Lake Chad basin and the other related wetlands is the driving force behind the expansion of the Sahel. Aquatic weeds generally roughly quadruple evapo-transpiration from the body of water they occupy. They are very productive plants, and sequester a great deal of CO2, converting it ultimately into soil, but for each molecule of CO2 they sequester, they also take one of H2O (carbohydrate), and transpire many more. The water is not reaching the lake, not recharging the aquifers, and not creating the “lake effect” rains the area used to have. Meanwhile, soil is being built up, raising the level of the terrain, filling in stream beds so that they are no longer functional.
What is needed is to control, and nearly eradicate these weeds, at what profit we can get from their biomass. To keep them under control, we will need companies that make a profit on their exploitation and control. Part of their clearance is the removal of the soil they have created that now clogs the waterways. There are many nearby places where that soil could be used, along with some of the charcoal as biochar.
A useful first step would be for some organization to get a hold of the equipment used to inspect food for contaminants such as heavy metals and insecticides, and determine on the spot whether a particular Typha stand is fit for human consumption, or not. I have a few suggested starting sites, where there are people ready to try. Most of it is probably safe, but where the people are is where the pollutant hazard is greatest.
The aquatic weed problem is partly natural and partly anthropogenic. Every dam built creates new environments for weed expansion, both upstream and downstream. The weeds are more tolerant of changes in the water level and take over both where there is more water and where there is less, and completely dominate those areas where it varies.
Check into Typha, see how much damage it is doing in Africa and everywhere else desertification is going on, and see how much it could be doing for them. Attached is a sketchy little plan I’m circulating for financing the control of Typha, to do with as you will. I’m more into “low-tech” charcoal now – it has such a low startup cost.
Written by: Steve Klaber