Water Retention Systems at Ananda Kalyanii

By Dmitry Ostapchuk

Due to climate changes that are increasingly being felt through extreme weather events, such as heat waves, high precipitation in a short period of time, extreme winds and soil erosion, it is necessary to adapt the land to the new weather conditions. Ananda Kalyani’s region of Cova da Beira is also strongly affected by such changes. The region has a relief with steep slopes and a soil with little impermeability so that, whenever there is heavy precipitation, the water is routed directly to the rivers at great speed, contributing to an abrupt increase in their flow and consequent floods.

Statistical data tell us that precipitation values in this region average 1082 mm per year [3]. However, there is seasonal variation in the probability and amount of monthly precipitation. The period when the daily probability of precipitation is below 20%, more commonly known as the dry period, lasts approximately 4 months, from the end of May to the end of September. In the same period the average accumulated precipitation is significantly below 50 mm per month. [2]

Therefore, in order to mitigate the consequences of periods of drought and torrential rains, one of the first challenges to consider when starting to work on the land itself is water management, particularly the concern of how to promote infiltration and conservation of water. The techniques of infiltration basins and ditches, widely used in permaculture, allow the retention of water in the soil and consequent preservation of nutrients, allowing the creation of sustainable, productive and biodiverse spaces, which in turn stimulate the prosperity of the native fauna and flora [4].

Retention basins (ponds) are structures intended to retain rainfall, contributing to the resolution of extreme floods and droughts and creating very rich microhabitats (Figure 1). On the other hand, infiltration ditches (in English swales) are built along the contour lines to follow the topographic design of a land, in order to increase the retention and infiltration of water in the soil (Figure 2). Both ponds and infiltration ditches are very effective water management tools using relatively low-cost natural elements from the site. The implementation of the two structures significantly reduces the speed of the flow of rainwater to the surface, which in turn has the following benefits [4]:

Figure 1: Retention basins under construction. Taken from [1].

Figure 2: Scheme of infiltration trenches. Taken from [5].

Figure 3: Some of the infiltration ditches (highlighted with orange ellipses) built as part of the workshop organized by EcoAtivo

  • retention of water in the system, introducing it into the water table;
  • reduction of soil erosion;
  • increased level of nutrients and organic matter content in the upper soil layer, improving soil fertility.

On September 17, 2021, Ananda Kalyani’s PCAP department “Ecoativo” hosted an infiltration trench construction workshop. The chosen place served this purpose perfectly: the part of a rocky slope with little vegetation that was constantly subject to the process of rainfall erosion. The constructed ditches were typically crescent-shaped and reinforced with the remains of the farm’s pruning. In order to make the trenches even more resistant, the following day, native trees were planted inside them (oaks, cork oaks, etc.). Figure 3 shows the result part of that work.


[1] Water retention in semi-arid environments with sandy soils

[2] Average climate and weather in Covilhã year-round

[3] Wikipedia. Covilhã weather

[4] Basins and retention ditches, improve water management and soil protection in LIPOR’s Adventure Park and Ecological Trail

[5] Infiltration ditches on contour lines or swales

Dmytro studies Computer Engineering at the University of Aveiro, and is also an enthusiast of environmental regeneratio