Eyebrow terraces / banquettes

Category:

Description

INTRODUCTION

Eyebrow terraces are a form of microcatchment water harvesting system. They are handmade microbasins, in the shape of an eyebrow, and often made from soil and stones. Their main goal is to collect runoff water from a small catchment area and infiltrate it into the soil. This way, it is stored in the root zone and will be available for crops. They are usually situated on hillsides and they can be used on slopes of up to 50%. The steeper the slope, the more the bunds have to be reinforced with stones. Eyebrow terraces work well in areas characterised by 200-600 mm of annual rainfall. Reinforcing eyebrow terraces with stones on steep slopes makes them more resistant to the increased water speed caused by the slope. Unlike some other forms of terracing, eyebrow terraces are not uninterrupted. Instead, they can be some meters apart. After completion, the pit uphill from the eyebrow may fill with sediments and soil and thereby terraces arise.

MECHANISM

Eyebrow terraces are usually built by scraping soil and stones together and putting them in place to form a ridge. The centre of each pit functions as a great location for a tree. Different types of interventions belonging to the microcatchment water harvesting systems can vary by the ratio between the catchment area and the cultivated area. This can vary between 2:1 and 10:1. Specifically, for the eyebrow terraces intervention, the catchment size is 5-50 m2 and the cultivated area is 1-5 m2.

OTHER

This technique has been tested, together with other rehabilitation measures, in Dhotra village, Jhikhu Khola watershed, Kabhrepalanchok district in Nepal over an overgrazed, almost barren land. About 130 pits were dug, and grass, fodder and trees were planted with the purpose of controlling and collecting the runoff in order to re-establish vegetative cover over the area.

To read more about it, please visit http://lib.icimod.org/record/28239/files/13.pdf

Additional information

Rainfall

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Slope

Land use

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Stones