As the saying goes; water is life. This is also true for the Himo Tree Nursery.
By nature, water scarcity was not a major issue at Kilimanjaro in years past. There are several large rivers that carry water from the mountain slopes to the lowlands throughout the year.
The hillside population developed an elaborate irrigation system hundreds of years ago to transport the water needed for agriculture to the fields. By means of the so-called gravity ditch technique, river water is conveyed in countless intersecting canals to the areas used for agriculture. Usually these channels have their beginning at the uppermost edge of the forest zone. For tapping, a quiet river spot is sought. There, a barrier of stones is built so that the water accumulates into a small pond. From there, the feed begins into a constructed channel. Excess water flows over the stone barrier further down the river.
Sometimes the channel is reinforced with concrete or stones, sometimes it is just a ditch.. Often you can also see bamboo or hollowed tree trunks that guide the water.
The canals are maintained by the local canal association. Users have to pay a fee for this. The amount of water desired determines the amount of the fee. Water withdrawal is closely monitored, and so we in the nursery also have frequent loud discussions with the people from the Water User Association.
A few decades ago, there was always enough water for everyone, but with the increase in population and the associated increase in demand for agricultural products, this has changed. In particular, the large acreages of sugar cane and rice in the Lowlands have huge water demands.
In old travelogues, for example, the village of Kahe is described as a lush green oasis with abundant wildlife. If you now drive to this place in the Lowlands, which is 22 km away from Moshi, you will find a rather dusty place with few trees.
But of course, climate change is also noticeable. The rainy seasons have shifted and become shorter but with very heavy rainfalls. So a lot of water comes down in a very short time, which the soil can not absorb so quickly. This means erosion and flooding.
To counteract this, we want to plant as many trees as possible. However, these trees need sufficient water when they are young.
Since the river water is heavily polluted when it starts to rain after a long dry period, we have now thought about how we can clean it naturally so that the filters of the pump and the drip irrigation do not always close immediately.
First, of course, roughly remove all leaves, sticks and garbage. Then we have filled the riverbed on about 10 meters length with different materials. Starting with larger stones, then getting smaller and smaller until we finally filled up to our inlet gravel.
Through this natural filter, we hope that after the next big rainstorm our water reservoir will be filled with reasonably clear water. Let's wait and see.
