The Fourth Cascade - Ravines and Streams

The Fourth Cascade - Ravines and Streams

DREVO Ravine & Stream Restoration System (RSRS)

The role of ravines and streams

Ravines and temporary streams are natural drainage channels in the mountain system. They receive water from the upper and middle slopes, redistribute it, retain sediment, and feed permanent streams and springs.

In a healthy mountain ecosystem, a ravine shouldn't be a deep erosional wound. It should be a stable riverbed with alternating rapids, calm areas, widenings, and floodplain pockets.

The main principle:

The ravine should not accelerate the water, but gradually dampen its energy, cleanse the flow and return some of the water to the ground.

Main tasks

The fourth cascade performs the following functions:

safe passage of floods;

decrease in flow rate;

reduction of deep erosion;

sediment retention;

groundwater replenishment;

restoration of streams;

formation of floodplain vegetation;

creation of habitats for animals.

Main threats

When ravines degrade, the following occurs:

deepening of the channel;

coastal erosion;

loss of fertile soil layer;

formation of mudflows;

siltation of lower areas;

destruction of roads and bridges;

reduction in spring nutrition.

Cascade structure

Each ravine consists of repeating functional elements.

1. Reception area

Receives water from the middle slope.

Main elements:

plant filter;

stone dividers;

distribution areas;

sediment traps.

2. Step Pools

Every few meters (the distance is determined by the slope and the estimated water flow) low stone thresholds are created.

Functions:

decrease in flow rate;

oxygenation of water;

prevention of bottom erosion;

longitudinal profile stabilization;

creation of natural steps.

Each threshold has:

solid foundation;

lateral fastening;

central or distributed drainage;

protection against undermining below the threshold.

3. Channel widening

An extended zone is provided after each threshold.

Purpose:

decrease in water speed;

sedimentation of sand and silt;

infiltration;

development of coastal vegetation;

formation of small backwaters.

The extensions must have gentle banks and not impede the passage of the design flood.

4. Nano-sediment traps

After areas with high erosion, special pockets are created for accumulation:

sand;

gravel;

organic residues;

wood;

seeds.

Peculiarities:

convenient access for maintenance;

possibility of natural overgrowth;

safe overflow.

The extracted material can be used to restore slopes.

5. Infiltration areas

In wide sections of the ravine, zones are created where some of the water seeps into the ground.

Used:

pebble filters;

large stone;

wood residues;

deep root system of plants.

Such zones help replenish groundwater and reduce the volume of rapid surface runoff.

6. Floodplain pockets

In places where the riverbed naturally widens, small floodplain areas are formed.

Their functions:

temporary retention of flood water;

accumulation of fertile sludge;

development of wet vegetation;

creation of habitats for amphibians and insects.

Floodplain pockets should not be completely isolated from the main channel.

Working in a drought

During the dry period the system should:

retain residual moisture;

maintain springs;

reduce overheating of the riverbed;

provide shading with water and vegetation;

maintain moist microbiotopes.

Even if the surface flow temporarily disappears, it is important to maintain the connection to the underground drainage.

Work during abnormal rainfall

During extreme rain:

water comes from the upper cascades;

rapids reduce the flow rate;

extensions take in some of the water;

sediments settle in traps;

infiltration zones absorb part of the volume;

the remaining flow passes safely down the riverbed.

Each element must work independently, without the risk of destroying the entire system.

Plant communities

The bottom of the riverbed

sedges (Carex spp.);

sytniki (Rush spp.);

local moisture-loving herbs.

Shores

willows (Salix spp.);

alder (Alnus spp.);

buckthorn (Alder buckthorn);

дёрен (Blood-red hornbeam).

Upper part of the banks

hazel;

viburnum;

hawthorn;

bird cherry;

local shrubs.

Arboreal layer

Depending on the region:

ash tree;

elm;

oak;

maple;

linden.

Trees are placed in such a way as to strengthen the banks, but not to create obstacles for the passage of floods.

Working with wood waste

Large trunks and root systems can be used as elements of natural engineering.

They help:

reduce water speed;

retain sediment;

create microenvironments;

retain moisture;

strengthen the banks.

However, such structures must be secured and must not create dangerous blockages.

Biological engineering

Used:

local mycorrhiza;

hydroseeding of native species;

biomats on eroded banks;

wood mulch above the flood line;

natural fibers for protecting young plantings.

Robotic restoration

DREVO Mountain Rover

Performed by:

device of thresholds;

creating extensions;

formation of sediment traps;

strengthening of banks;

planting of plants.

TREVO AeroSense Drone

Controls:

change of channel;

sediment volume;

erosion rate;

humidity;

vegetation condition;

consequences of floods.

WOOD AI

Analyzes:

flow hydraulics;

threshold stability;

sediment accumulation;

need for maintenance;

forecast of riverbed changes.

Monitoring

Living Mountain Observatory records:

water consumption;

water level;

turbidity;

temperature;

coastal humidity;

flow rate;

volume of accumulated sediment;

the state of coastal vegetation.

Integration

The fourth cascade combines:

DREVO Mountain Sponge— regulation of water inflow;

Mountain Springs Recovery— feeding of springs;

Mountain Forest Corridors— restoration of coastal forests;

Living Mountain Observatory— monitoring;

Mountain Digital Twin— digital model of the riverbed;

TREVO AeroSense Drone- remote monitoring;

WOOD BioFire System— providing access to water for fire-fighting activities.

Expected results

After the restoration of the ravine and stream system, the following is expected:

reduction of deep erosion;

reduction of flood velocity;

increased infiltration;

accumulation of fertile sediments;

restoration of coastal vegetation;

coastal stabilization;

improving water quality;

increasing biodiversity;

reducing the risk of mudflows;

stable power supply of the lower cascades.

Conclusion

The fourth cascade is a transitional link between slope processes and the river network. Its purpose is to transform a destructive flow into a controlled natural system, where rapids, channel widenings, sediment traps, infiltration areas, and floodplain pockets combine to reduce the energy of the water, restore the soil, and maintain the stability of the entire mountain ecosystem. It is here that the transformation of surface runoff into a long-term water resource for forests, springs, and valleys is completed.