DREVO Watershed Architecture
Working with Watersheds: Calculating from Mountain Peaks to Lowlands
Mountain restoration cannot be carried out through individual plantings, terraces, or reservoirs. The project's primary unit of calculation isan entire catchment area— the area from which rain, melt and groundwater collects into a common channel, river, lake or coast.
The whole system is designedtop down:
mountain ridge → upper slope → middle slope → lower slope → gorge → valley → floodplain → lowland → coast
But engineering calculations are performed simultaneously and in the opposite direction:
from the most vulnerable lowland up to the sources of formation of dangerous runoff.
This allows not only to drain water, but also to control its speed, volume, direction, retention, penetration into the ground, and the safe passage of extreme floods.
1. Watershed as a single living system
Each major basin is divided into:
main watershed;
sub-basins;
micro-catchments;
temporary channels;
permanent streams;
ravines and couloirs;
sediment accumulation zones;
spring areas;
marshy areas;
floodplains and lowlands;
places where water flows out to the sea.
For each level, its own calculation and restoration plan is created.
The main task is not to stop the water completely, which is impossible and dangerous in the mountains, but:
to retain some of the precipitation at altitude;
increase infiltration;
slow down surface runoff;
distribute the flow into several safe directions;
reduce the height of the flood wave;
retain stones, wood and sediment;
maintain an emergency route for extreme traffic.
Modern hydrological models treat a basin as an interconnected system of precipitation, infiltration, surface runoff, channel water movement, evaporation, soil moisture, and groundwater recharge. This approach is used, for example, in HEC-HMS to model branched drainage systems.