Restructuring the effluent web in Italy

NWRM

Application scale

Field Scale

Installation date

2009-05

Age

Performance timescale

< 1 year

Design capacity description

The measures were designed and modeled to protect from flood events generated by precipitations with a 30-years return time.

Basis of design

The measures were designed and modeled to protect from flood events generated by precipitations with a 30-years return time.

Constraints

No info

Favourable preconditions

No info

Outflow volume

Outflow volume unit

m3/sec

Design contractual arrangement

No data

Design consultation activity

No data

Design land use change

No data

Design authority

Authority type	Role	Name	Comments
Local water authority	Initiation of the measure	Consorzio Acque Risorgive	Consorzio di bonifica: local water authority in charge of managing and maintaining the irrigation network as well as the provision of irrigation water
Local water authority	Implementation	Consorzio Acque Risorgive
Other	Financing	Veneto Region	Provincial Administration - Funding (through the †œPlan for diffuse pollution prevention and restoration of water in the draining basins of the Venice Lagoon†)
	Determination of design details of the measure	Ingegneria 2P e Associati	External consulting firm (contractor) - design of measures
	Other	Bruno Boz †“ free-lance professional and member of CIRF	External Consulting (design, implementation and evaluation)
	Monitoring	University of Bologna

Key lessons

The visible positive impact and effectiveness of the measures was a key success factor, as well as a key element to increase environmental awareness in the area. In particular:
- The ability of the measures to address two pressing environmental issues in the area, while raising environmental quality at the same time, is a key success factor.
- Flooding events significantly decreased after the implementation of measures.
- The measures created pleasant natural environments and residents are now using the area for recreation (walking, biking). This has a great value in an area otherwise dominated by monoculture, with very little natural spaces.

Financing difficulties

Success factor(s)

Success factor type	Success factor role	Comments
Other	main factor	The main success factor is the evident effectiveness of the measures! During the implementation phase, some residents complained for the annoyance (e.g. the dust lifted by the machinery). However, during the first intense precipitation, the rivers/ channels didn't overflow (they would have before implementation), so residents understood the key role of measures for flood mitigation.
Other	main factor	The ability of the measures to address two pressing environmental issues in the area, while raising environmental quality at the same time, is a key success factor.
Attitude of the public	secondary factor	The measures created pleasant natural environments and residents are now using the area for recreation (walking, biking). This has a great value in an area otherwise dominated by monoculture, with very little natural spaces. Furthermore, the possibility of doing recreational activities has raised residents' awareness and interest towards the importance and role of measures, as well as on the importance and value of natural areas.
Other	secondary factor	The overall decrease of N levels in the Venice lagoon, which followed the implementation of these and other similar measures in several sites of the draining basin, contributed to gain a positive public perception of these measures.
Financing possibilities	main factor	Availability of funds for this type of measures created by the Plan for the Venice Lagoon

Financing

Financing type	Comments
National funds	The Veneto Region, through the "Plan for diffuse pollution prevention and restoration of water in the draining basins of the Venice Lagoon" financed measures of re-calibration of riverbeds aimed at the renaturation of the hydraulic web, to increase the time of permanence of water and phytodepuration processes in the draining basin.

Barrier

Barrier type	Barrier role	Comments
Other	secondary barrier	The design of intervention was contracted to an external engineering firm, which did not have a capillary knowledge of the area and the territory, so this created some problems
Other	secondary barrier	In some cases, negotiations for expropriations posed some challenges
Other	secondary barrier	After implementation, there were some little problems with farmers: in some cases, trees and plants cast shadows on crops.

Driver

Driver type	Driver role	Comments
Availability of subsidies	main driver	The Plan for the Venice Lagoon subsidized interventions to reduce eutrophication. The Consorzio chose NWRM because these measures also address flooding issues, quite common in the area
Other	secondary driver

Policy description

The project tackles two problems at the same time:
- Retain part of the N and P loads from agricultural activities in the basin through phytodepuration ,thus reducing the amount of nutrients reaching the Venice Lagoon (the Lagoon is affected by serious eutrophication issues)
- Reduce the incidence and intensity of flood events in the area. Flooding issues had increased in the decades before the interventions mainly because the sections of the drainage channels were too narrow to contain water discharges in critical periods of the years. When the channels were built, their size was sufficient to contain high discharges, but then the landscape had changed: urban sprawling increased impermeable land, and also agricultural drainage practices (e.g. tubular drainage)had changed increasing discharge into channels.
According to the project's authors, in the framework of integrated landscape planning these two objectives proved to be totally synergic

Quantified objectives

Expected impact on water quality (forecast based on experimental parameters from previous applied studies, caluclated in the design phase)
Total N reduction: 12.73 t/year
Total P reduction: 0.64 t/year

Part of wider plan

Policy target

Target purpose
Pollutants Removal
Peak-flow reduction
Improved Biodiversity
Oher Societal Benefits

Policy pressure

No data

Policy area

No data

Policy impact

No data

Policy wider plan

Wider plan type	Wider plan focus	Name	Comments
		Plan for diffuse pollution prevention and restoration of water in the draining basins of the Venice Lagoon	The "Plan for diffuse pollution prevention and restoration of water in the draining basins of the Venice Lagoon" (entered into force in 2000) is aimed at addressing the serious eutrophication issues affecting the Venice Lagoon. The draining basin of the Venice Lagoon is in fact characterized by intensive agriculture, responsible for the discharge of large amounts of nutrients (N and P) into the lagoon. The Veneto Region, through the "Plan for diffuse pollution prevention and restoration of water in the draining basins of the Venice Lagoon" financed measures of re-calibration of riverbeds aimed at the renaturation of the hydraulic web, to increase the time of permanence of water and phytodepuration processes in the draining basin.

Policy requirement directive

No data

Direct benefits information

Information not available

Ancillary benefits information

Information not available

Costs investment information

Information not available

Costs operation maintenance

Information not available

Costs total

4131655

Costs total information

Total financial costs

Compensations scheme information

Measures were implemented on private land, which was thus expropriated. Expropriation involves compensation for landowners, although the price paid is lower as compared to a purchase of land on the market.

Ecosystem improved biodiversity

Information on Ecosystem improved biodiversity

Overall, the environmental quality has increased, and new habitats were created. However, data on biodiversity improvements are not available

Ecosystem provisioning services

Information on Ecosystem provisioning services

Although measures have had a positive impact on water quality, water from rivers and channels is not used for human consumption, so "provision of clean water" has not been included in the list of ecosystem services.

Ecosystem impact climate regulation

Increased permanent biomas

Information on Ecosystem impact climate regulation

In buffer zones (but limited area)

Information on Peak flow rate reduction

Overall, the peak flows discharged by rivers and channels to the Dese river decreased from 29 m3/s to 25 m3/s (13.8% overall reduction of peak flows into the Dese river)

Information on Ecosystem flood control volume

Overall, the peak flows discharged by rivers and channels to the Dese river decreased from 29 m3/s to 25 m3/s (13.8% overall reduction of peak flows into the Dese river)

Water quality overall improvements

Positive impact-WQ improvement

Information on Water quality overall improvements

Water quality improvements: the simulation conducted in the design phase indicate that a significant amount of nutrients can be retained by the measures. In addition, this is just one intervention areas, as similar measures were implemented in several other sites by the Consortium, as part of the Plan for the Venice lagoon: and, overall, since these interventions started the N content in the lagoon has actually decreased.

Information on Water quality Improvements (P)

Expected impact (forecast based on experimental parameters from previous applied studies)
Total P reduction: 0.64 t/year

Information on Water quality Improvements (N)

Expected impact (forecast based on experimental parameters from previous applied studies)
Total N reduction: 12.73 t/year

Monitoring impacts effects

Monitoring location

Unknown

Monitoring parameters

Monitoring is supposed to be carried out by the Regional Agency for Environmental Protection, but actually little has been done so far. The Consorzio carried out some monitoring in some sites, but these data were not shared.
Specific monitoring of N retention was carried out in another site, where similar measures were also implemented by the Consorzio, in the experimental site NICOLAS.

National Id

Italy_02

Site name

Draining basin of the Venice Lagoon - Venice province

Summary

The case study is located in the draining basin of the Venice Lagoon. It is characterized by intensive agriculture and by a web of drainage channels discharging into the rivers. This case study, in particular, includes measures on the drainage channels discharging into the Dese river, one of the main water bodies of the Venice Lagoon basin.
The Veneto Region, through the “Plan for diffuse pollution prevention and restoration of water in the draining basins of the Venice Lagoon” financed measures of re-calibration of riverbeds aimed at the renaturation of the hydraulic web, to increase the time of permanence of water and phytodepuration processes in the draining basin. In this framework, the Consorzio Acque Risorgive implemented a series of extended interventions on the area under its responsibility. This case study was implemented as part of these interventions.
In particular, it aimed at re-structuring the effluents of the mid course of the Dese river (Rio S. Martino, Rio S. Ambrogio and Scolo Desolino). Such effluents are mostly draining channels, draining water from agricultural fields to the Dese river. The primary objective was the reduction of the amount of N and P reaching the Venice lagoon through phytodepuration. However, at the same time the project carried out the restoration of the draining channel web aimed at reducing flooding issues affecting the area. Over the years, the area has in fact been subject to massive urban development (new residential and industrial areas), with consequent soil sealing and culverted effluents: this had a devastating effect on the hydrological system. The strong floods of 2006 and 2007 on the city of Mestre, for example, were a consequence of this.
The following measures were implemented: (i) Riparian buffer zones; (ii) Creation of wetlands; (iii) River bed enlargement; (iv) Creation and reconnection of floodplain and new buffer strips; and (v) Channel naturalization, creation of new meandering channel.
The ability of the measures to address two pressing environmental issues in the area was a key success factor. The measures proved in fact very effective in reducing nitrogen loads in effluents and, ultimately, into the Venice Lagoon, as well as mitigating flood risk in the area. During the implementation phase, some residents complained for the annoyance (e.g. the dust lifted by the machinery). However, during the first intense precipitation, the rivers/ channels did not overflow (they would have before implementation), so residents understood the key role of measures for flood mitigation. Furthermore, the overall decrease of N levels in the Venice lagoon, which followed the implementation of these and other similar measures in several sites within the draining basin, contributed to gain a positive public perception of these measures.

NUTS Code

Veneto

RBD code

ITA

Transboundary

Data provider

Gloria De Paoli, ACTeon

Longitude

12.0629

Latitude

45.343

EEA core metadata

Contents

cs-it-02-final_version.pdf