CONSTRUCTED POROUS RIFFLE IN THE URBAN PERIPHERY OF LYON (FRANCE)

image
image
image

Description

Location

Demosite Location
Demosite Location

Sketch

Demosite Location

Information about lithology/geochemistry:

Gneiss and granite bed-rocks covered with alocrisol (granitic brown acid soil) and sandy-silt to silty-sand colluvial into valleys.


Main Description

  • The Yzeron river basin is 147 km2 in area with a population is of 144 000 inhabitants (1 354 000 for Lyon metropolitan).
  • Demosites are located N45°44’38.50’’–E4°41’24.49’’ and N45°45’28.24’’–E4°45’04.09’’ on seasonal rivers.
  • This project focuses on the enhancement of natural regulating services by increasing local biodegradation capacity of soils and stream sediments to trap and naturally process polluted waters delivered by urban sewage systems.
  • The demosites are part of the Field Observatory for Urban Water Management (http://www.graie.org/othu/index.htm) itself included in the European-LTER network (https://data.lter-europe.net/deims/site/czo_eu_fr_030).

Conserve Ecohydrological processes in natural ecosystem

NO

Enhance ecohydrological processes in novel ecosystem

YES

Apply complementary Ecohydrological processes in high impacted system

YES


This table presents the different categories of ecosystem services that ecosystem can provide, divided in:

Provisioning Services are ecosystem services that describe the material or energy outputs from ecosystems. They include food, water and other resources.

Fresh water: Ecosystems play a vital role in the global hydrological cycle, as they regulate the flow and purification of water. Vegetation and forests influence the quantity of water available locally.

Regulating Services are the services that ecosystems provide by acting as regulators eg. regulating the quality of air and soil or by providing flood and disease control.

Moderation of extreme events: Extreme weather events or natural hazards include floods, storms, tsunamis, avalanches and landslides. Ecosystems and living organisms create buffers against natural disasters, thereby preventing possible damage. For example, wetlands can soak up flood water whilst trees can stabilize slopes. Coral reefs and mangroves help protect coastlines from storm damage.


Waste-water treatment: Ecosystems such as wetlands filter both human and animal waste and act as a natural buffer to the surrounding environment. Through the biological activity of microorganisms in the soil, most waste is broken down. Thereby pathogens (disease causing microbes) are eliminated, and the level of nutrients and pollution is reduced.

Ecosystem services "that are necessary for the production of all other ecosystem services". These include services such as nutrient recycling, primary production and soil formation.

Habitats for species: Habitats provide everything that an individual plant or animal needs to survive: food; water; and shelter. Each ecosystem provides different habitats that can be essential for a species’ lifecycle. Migratory species including birds, fish, mammals and insects all depend upon different ecosystems during their movements.


Maintenance of genetic diversity: Genetic diversity is the variety of genes between and within species populations. Genetic diversity distinguishes different breeds or races from each other thus providing the basis for locally well-adapted cultivars and a gene pool for further developing commercial crops and livestock. Some habitats have an exceptionally high number of species which makes them more genetically diverse than others and are known as ‘biodiversity hotspots’.

Cultural Services corresponds nonmaterial benefits people obtain from ecosystems through spiritual enrichment, cognitive development, reflection, recreation, and aesthetic experiences.

Lifezones

Demosite Location
Life zone
Cool Temperate
Montane
Moist Forest

Precipitation
PPT(mm/yr): 734.0

Temperature
T(ºc): 11.6

Elevation of demosite: 314.0 meters above sea level
Humidity: Humid
PETr (by year): 0.93

EH Principles

Quantification of the hydrological processes at catchment scale and mapping the impacts

Distribution of ecosystems and their relevant processes (ex: metabolism=water and nutrient uptake and retention; biomass production)

Ecological engineering (integration, dual regulation and biotechnologies in catchment scale for enhancement of ecological potential)

ECOHYDROLOGY ENGINEERING SOLUTIONS

Into seasonal urban stream : constructed porous riffles to enhance the trapping of sewage organic pollution by porous sediment and its biodegradation by microbial activity.

Ecohydrological Infrastructure
Faunatechnology
Phytotechnology
Hydrological Flow

Major Issues

Social ecohydrological system

EH Objectives

Water:
Biodiversity
Services
Resilience

EH Methodology

  • This EH methodology is to amplify the self-purification capacity of soil and river bottom sediment that receive polluted urban runoff. It makes use of the hydrological rinsing and dewatering natural phases to promote the pollution storage, biodegradation and natural renewal of the biofilter installed.

Catchment Ecohydrological sub-system

Objectives

  • From several years of field experiment with a huge recording data set we can confirm that a sequence of 3 porous weirs installed in a small seasonal water course can fully trap and process organic pollution introduce during rainy events. This system is self maintained by high flow waters which regenerate the biofilter in place. The principle is in course of replication in another small water course where it should help the receiving main stream to recover its good ecological status.

  • Stakeholders

  • SAGYRC : The river syndicate office is a legal entity in charge to meet the WFD objectives

  • The OTHU field observatory for urban water management gathers 20 research labs since year 2000, working on innovative solutions to reduce the urban footprint on the local water resource

  • The Lyon metropolitan water direction is a partner of both the SAGYRC and the OTHU.

  • Catchment Sociological sub-system

    Activities

    • SAGYRC, is in charge to meet the WFD objectives. It implements actions all over the river systems since 2000, regarding for water quality, ecological quality, rules for water resource sharing during low flow period, protection of riverine inhabitants against flooding, river geomophological rehabilitation, education and training of people to river functioning, protection and rehabilitation of cultural heritage. The SAGYRC supports the implementation of the demosite in 2018 for the river selfpurification amplification in coordination with a project for flood control

    • The Water direction of Lyon metropolitan supports the OTHU research project for more than 18 years. It is involved in the second demo-site where the objective is to reinfiltrate urban runoff after cleaning by soil and plant filter. The water direction is also in charge to renew of old main sewers that collect urban waters from the upper watershed to a centralized WWTP.

    Expected Outcomes

    • Reach WFD objective for the water mass of concern, by Increasing the carrying capacity of seasonal small water courses to cope with urban unmanageable runoff pollution, increase their resilience to future urban development


    • Develop a river reach scale mapping of the naturally varying carrying capacity all along the river network as to consider it in future land developments.


    Latest Results

    • Confirmed that artificial riffles can help to trap and process the organique pollution issued by a combined sewer overflowing system.

    Contacts

    Pascal Breil

    • pascal.breil@irstea.fr
    • www.irstea.fr
    • IRSTEA- Riverly research unit

    Overview

    Back

      7, place de Fontenoy 75007 Paris - France

    Development: Copyright © 2015 CIH / All rights reserved. | Design: Copyright © 2012 Little NEKO / All rights reserved.