An eco-sustainable approach to polluted sediment management in European drainage networks

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Acknowledgements

Renato Iannelli, per la fiducia riposta nell’affidarmi la scrittura di un progetto importante e per avermi dato la possibilità di confrontarmi con una sfida nuova, al di fuori del ristretto campo di studio.

Eleonora Peruzzi, per tutto il lavoro svolto insieme, per tutti i giorni nei quali la scadenza per la presentazione della progetto sembrava sempre troppo vicina e per avermi aiutato a capire che, a volte, è necessario staccare e prendersi una pausa.

Fabio Masi, Giulio Conte, Costantino Raspi, Grazia Masciandaro per aver contribuito alla genesi e crescita del progetto. Marco Monaco, Presidente CBV, e Antonio Coppola, tecnico CBV, per la disponibilità e l’esperienza sul campo che mi hanno trasmesso, rendendo il nostro lavoro più vicino alla realtà.

La mia famiglia per avermi supportato e sopportato in questi anni. Nulla sarebbe stato possibile senza di loro. La zia Gianna che avrebbe tanto desiderato essere a Pisa in questo giorno.

Elena, per avermi preso per mano ed aver avuto la pazienza e la costanza di capirmi in ogni momento del mio faticoso percorso personale. Senza di lei, forse, non sarei mai riuscito ad affrontare paure e debolezze che bloccavano la mia vita.

Sara per essere semplicemente l’Amica di una vita.

Alberto, per le innumerevoli esperienze vissute insieme, per gli abbracci nel momento del bisogno, per i sogni condivisi e per quelli ancora da condividere.

Luca, per tutte le esperienze da coinquilini, le indimenticabili schitarrate e le pacche sulle spalle nei momenti difficili. Carmen per la sua amicizia profonda e sincera. Monica, per le tante camminate e nuotate insieme.

Gli amici di sempre (Nicola, Ivan, Roberto, Pierluigi, Valentina, Leonardo,

Gianluca ed Andrea), quelli del “prefestivo” (in particolare Claudia, Andrea e Denise) e di “Praticelli” (Stefano, Alessandra, Angela e Cristina).

I compagni di avventure in montagna del G.A.U., in attesa di vivere insieme la prossima. I nuovi amici “spezzini” ed, in particolare, Francesca. Tutti i colleghi di studio e, specialmente, Alessandra per i suoi mille consigli. Franceschino senza il quale il Dipartimento di Idraulica non sarebbe lo stesso.

Lorenzo Pisa, 27 febbraio 2018

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Sommario

I sedimenti sono parte integrante dei corpi idrici e ne condividono un comune destino in caso di contaminazione. Ospitano una notevole varietà di ecosistemi, ma possono diventare una importante fonte di contaminazione differita nel tempo. Tuttavia, solo negli ultimi decenni si sta sviluppando una sufficiente consapevolezza su questo tema. Nello stesso tempo, il concetto di sostenibilità delle attività umane è diventato centrale in ogni tipo di approccio verso il territorio.

La gestione dei sedimenti contaminati è un problema complesso, in bilico tra gli obblighi derivanti dalla politica dei rifiuti ed una legislazione spesso frammentaria e controversa. I comprensori di bonifica sono un caso emblematico di queste difficoltà. La morfologia del territorio porta alla deposizione di una notevole quantità di sedimenti che, se mal gestita, tende ad incrementare il rischio alluvionale. Il reticolo idrografico raccoglie acque di scolo da aree agricole ma, in caso di vicinanza di complessi urbani o produttivi, può anche ricevere il dilavamento di pavimentazioni stradali od inquinanti industriali. La gestione è generalmente affidata ad enti di livello locale, che non usufruiscono delle grandi risorse di altre realtà più importanti, pur condividendo le medesime problematiche.

Questa tesi propone un approccio sostenibile alla gestione dei sedimenti contaminati all’interno dei comprensori di bonifica, tenendo conto della frequente limitatezza di investimenti ed evitando di incorrere, per quanto possibile, nei pesanti oneri della politica dei rifiuti. Tecnologie di decontaminazione semplici ma efficaci, riduzione dell’entità dei trasporti, riutilizzo del materiale decontaminato, coinvolgimento e sensibilizzazione degli stakeholder sono concetti chiave in questa ottica. Centrale è il ruolo assegnato agli strumenti di supporto alle decisioni.

Un intenso lavoro di ricerca bibliografica è stato necessario per acquisire le basi conoscitive e concettuali necessarie. Sono stati analizzati due casi studio in Italia e Polonia, al fine fornire ulteriori elementi di comprensione.

Le idee e le strategie proposte sono confluite nella scrittura di una proposta di Progetto LIFE all’Unione Europea, allo scopo di dare maggiore visibilità ed internazionalità ad una esigenza diffusa sul territorio ma, spesso, poco conosciuta.

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Abstract

Sediments are an integral part of water bodies and share a common destiny in case of contamination. They host a remarkable variety of ecosystems, but they may become an important source of deferred contamination over time. Notwithstanding, only in the last few decades sufficient awareness has been developing in this sense. At the same time, the concept of sustainability of human activities has become central in every kind of approach to the territory.

Management of contaminated sediments is a complex issue, poised between the obligations arising from waste policy and an often fragmented and controversial legislation. The remediation areas are an emblematic case of these difficulties. The morphology of the territory leads to the deposition of a considerable amount of sediment, which, if poorly managed, tends to increase the flood risk. The hydrographic network collects waters from agricultural areas but, in the case of proximity to urban or productive complexes, may also receive the urban runoff or industrial pollutants. Management is generally entrusted to local level bodies, which do not benefit from the large funding of other entities, while sharing the same problems.

This thesis proposes a sustainable approach to the management of contaminated sediments within drainage areas, taking into account the frequent limitation of investments and avoiding, as far as possible, the heavy burdens of waste policy. Simple but cost-effective remediation technologies, reduction of road transport amount, reuse of decontaminated material, stakeholder engagement and awareness raising are key concepts in this perspective. Central is the role assigned to decision support tools.

An intense work of bibliographic research provided the necessary knowledge and conceptual bases for developing innovative approaches. Two emblematic case studies were analysed in Italy and Poland in order to provide further insights.

The ideas and strategies proposed were merged into a LIFE project proposal for European Union funding. The proposal had the main aim of giving greater visibility and internationality to a widespread need in drainage and irrigation areas all over Europe. Widespread, but, often, not known enough.

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List of abbreviations

AHP Analytic Hierarchy Process

BTEX Benzene, Toluene, Ethlybenzene and Xylenes

CBV Consorzio di Bonifica 4 Basso Valdarno (Drainage and Irrigation Authority of Basso Valdarno)

CDBP Canal and Ditches Bank Plant ch. chapter

CNR Italian National Research Council CTP Central Treatment Plant

ed. editor

EKR Electro Kinetic Remediation EQS Environmental Quality Standard

EQSD Environmental Quality Standard Directive EU European Union

EU FP7 European Union Seventh Framework Programme for Research and Technological Development

excl. excluding fig. figure

GM Gdańskie Melioracje (Drainage Authority of Gdańsk) GUT Politechnika Gdańska (Gdańsk University of Technology) incl. including

LCA Life Cycle Analysis MCA Multiple Criteria Analysis

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List of abbreviations

MCDA Multiple Criteria Decision Analysis PAH Polycyclic Aromatic Hydrocarbon par. paragraph

SMG Sediment Management Guidelines SMP Sediment Management Plan TPH Total Petroleum Hydrocarbon

UMG Gmina Miasta Gdańska - Urząd Miejski w Gdańsku (Municipality of Gdańsk)

UNIPI University of Pisa US United States

VOC Volatile Organic Compound WFD Water Framework Directive

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INTRODUCTION

The quality of surface and deep-water bodies is a cause of concern all over the world for the risks posed to the environment and to human health. A large amount of literature has been produced on this issue and legislative interventions have been followed at an ever-increasing pace at both the European (Water Framework Directive) and national level. In the same time, the concept of sustainability of human activities has become central in any in any kind of approach to the territory. Nevertheless, it have been only in the last decades that a sufficient accent have been posed to sediments and a relevant awareness have been developed. Indeed, they share the same water bodies’ destiny in case of contamination, they host a great variety of ecosystems, but they may also become an important source of deferred contamination over time.

To maintain the functionality of many human works and to protect against flood risk, it is necessary to consider sediments deposited in water bodies. The management of these sediments, when they are contaminated, is a complex task: on the one hand, there are the requirements of the waste policy (high costs for sediment transport and landfilling); on the other, an often-fragmented legislative framework, which does not deal with sediment issues in a unique regulatory body.

Drainage areas are an emblematic case of these difficulties. As they consist of essentially flat lands, they are regularly subject to the deposition of a considerable amount of sediment. When poorly managed, this phenomenon tends to inevitably cause a flood risk increasing. The hydraulic network that characterises drainage districts collects waters from agricultural areas with their pollutant load and, in case of proximity to urban or productive complexes, it may also convey urban runoff and industrial pollutants.

These areas are generally managed by local authorities, which do not benefit from the large funding of important port infrastructures or navigable canals, although they share similar management problems.

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This thesis proposes a different approach to the management of contaminated sediments in drainage areas. Our aim is contributing to the implementation of a sustainable management, which takes into account the limited availability of investments, avoiding, as far as possible, the heavy burdens required by waste policy. Simple but cost-effective remediation technologies, reduction of road transport amount, reuse of remediated material, stakeholder involvement and awareness raising are key concepts in this perspective. Central is the role assigned to decision-support tools, in order to facilitate the choice of the most appropriate management strategy for each specific context.

An intense work of bibliographic research concerning the management of sediments and drainage areas, and remediation technologies provided the necessary knowledge and conceptual bases for developing innovative strategies. Two emblematic case studies were analysed in Italy and Poland in order to provide further insights.

The information from dedicated research, together with envisaged ideas and strategies, were merged into a LIFE Project Proposal for the European Union funding. An Italian-Polish mixed team supported the Proposal with the main aim of gaining greater visibility and internationality to a widespread need in drainage and irrigation areas all over Europe. Widespread but, often, not known enough.

The dissertation is organized as follows.

Chapter 1 introduces the context of drainage and irrigation authorities at European level, explaining their role in the management of drainage districts. A focus on two case studies is provided.

Chapter 2 directly considers sediments and describes main aspects related to their management (environmental, legislative, economic, etc.). The same case studies are analysed from several points of view. In order to outline the context in which we move, a general overview about drainage and irrigation networks and their management is given, paying particular attention to recent environmental management concepts.

Chapter 3 deals with existing sediment remediation technologies. After a general discussion, it focusses on three of them, which are particularly appropriate for the envisaged management approach.

On the basis of information gained in Chapters 1-3, Chapter 4 presents an eco-sustainable approach to polluted sediment management tailored for the exigencies of drainage and irrigation districts. A decision-support tool for the choice among different remediation strategies is outlined as well.

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Chapter 5 introduces an attempt to put the theorized principles into practice: ECOSED LIFE Proposal. This Project was presented to European Union for funding in September 2016.

Chapter 6 provides concluding remarks as well as a brief overview of the possible future work.

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1) DRAINAGE AUTHORITIES AND THEIR ROLE

IN DRAINAGE AREA MANAGEMENT

1.1 The importance of drainage networks

Hydraulic drainage networks are necessary in order to valorise land by means of water table control in soil. This usually takes place in rural areas with the aim of making them more suitable for crop production [1]. We may find drainage networks in urban context with the aim of protecting from flood risk. In this case, they receive the polluted storm water coming from paved surfaces as well.

Agricultural drainage ditches are essential for the removal of surface and ground water in poorly drained agricultural landscapes and mediate the flow of pollutants from agroecosystems to downstream water bodies [2]. Ditches provide valuable wet vegetated non-cropped habitats to both aquatic and terrestrial taxa, supply food resources lacking in dry and intensively managed cropland, and perform connectivity functions within a wider landscape. Some functions of drainage ditches, such as regulating water flow and nutrient retention, are likely to depend on the composition and structure of their biological communities [3].

1.2 The role of drainage authorities

Drainage authorities and stream/basin authorities are public bodies that share similar objectives on one hand, since both of them address management of water bodies, but are characterised by important differences and perspectives on the other hand.

The main dissimilarity are the following [4]:

- A drainage authority usually handles drainage and provides flood protection while a stream/basin authority has a wider perspective and may influence the

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ecological destiny of a particular river (e.g. it may determine water flow and manage health hazard from stream).

- Drainage authorities generally have a local dimension and are composed almost solely of local government representatives. Stream/basin authorities have a more variegated composition, being composed up to representatives of national policy.

Although Drainage Authorities role is concentrated on the minor hydrographical network, the implications of their work is of primary relevance for wider areas and impact population and numerous economic activities.

The main fields of intervention are traditionally the following:

- Drainage network management: The drainage network has to guarantee sufficient discharges (in order to reduce flood risk) and a proper height of the water table (in order to establish the best possible conditions for agriculture). Water and sediment quality is a relevant concern for Authorities as well. Indeed, any pollution in a drainage network will be unavoidably discharged into the receiving water body, affecting human health and activities in wide areas. - Irrigation network management: Through irrigation network, authorities may

guarantee a proper supply of fresh water for agriculture. This is particularly true during hottest and driest months of the year (the relevance is higher in southern part of Europe) and for drought-sensitive crops.

- Water facilities: Drainage and irrigation network may work properly thanks to a wide variety of water facilities (e.g. drainage pumping stations or retention tanks). Drainage authorities have to guarantee the proper functioning of these facilities through regular maintenance of mechanical parts, dredging and any other necessary operation.

- Spatial planning: Drainage authorities also contribute to the spatial planning of the managed districts. In order to operate and organize the water network at best, they draft plans, which have to respect higher-level tools like river basin management plans.

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Authorities perform an ordinary (e.g. grass and vegetation mowing) and extraordinary (e.g. ditches resizing or dredging, and bank reinforcement) maintenance of networks during the whole year.

In the last decades, a more modern management perspective is starting to be spread around: the so-called ‘environmental management’ is becoming an important activity of some of these boards. This approach does not only address technical exigencies by traditional engineered interventions, but has a wider view involving environment and naturality of canals and ditches. We will briefly touch this argument in Par.2.7.

1.3 Drainage authorities at European and national level

Drainage and Irrigation Consortia are the Italian administrative boards for drainage and irrigation water management. They are in charge of periodically dredging canals to maintain their hydraulic functionality. Similar authorities exist in many other European nations and have resembling organization, based on self- government and self-financing, and the similar functions for drainage, irrigation and protection of territories.

At a European level, EUWMA (European Union of Water Management Associations) represents public, local and regional water management organizations from nine EU member states: Belgium, Italy, Hungary, Germany, France, Spain, Portugal, United Kingdom and the Netherlands (see Table 1). Hence, it is one of the most relevant actors in this field. EUWMA members are public institutions with legal powers. They are umbrella organisations in EU member states representing authorities responsible for regional and local water management (over 8.600 individual organisations, covering around 55 million hectares) [5].

EUWMA was established in 1996 with the primary aim to increase cooperation between European Water Management Associations and to provide relevant information, position papers and policy documents to national governments, the European Commission, the European Parliament and other relevant institutions. In addition, EUWMA promotes the exchange of knowledge and best practices between members [5].

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EU MEMBER WATER MANAGEMENT

ASSOCIATION ASSOCIATION WEBSITE

Belgium

Vereniging Van Vlaamse Polders en Wateringen

(VVPW)

www.vvpw.be

France Association Syndicales

Autorisées (ASA) www.asainfo.fr

Germany

Deutscher Bund der verbandlichen Wasserwirtschaft (DBVW)

www.dbvw.de

Hungary Vízgazdálkodási Társulatok

Országos Szövetsége (VTOSZ) www.tir.hu

Italy Associazione Nazionale

Bonifiche e Irrigazioni (ANBI) www.anbi.it

Portugal Federaçao Nacional de

Regantes (FENAREG) www.fenareg.pt

Spain

Federacion Nacional de Communidades de Regantes

de España (FENACORE)

www.fenacore.org

The Nederlands Unie van Waterschappen www.dutchwaterauthorities.com

United Kingdom Association of Drainage

Authorities (ADA) www.ada.org.uk

Table 1 - A Summary of EUWMA members [5].

In the following pages, we will describe the drainage authorities’ framework in each of the nine-abovementioned countries. This information may be found in [5].

1) BELGIUM

Vereniging van Vlaamse Polders en Wateringen (VVPW)

NUMBER OF MEMBERS: 52 of the 63 polders and wateringen. STAKEHOLDERS IN BOARD: Landowners.

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TASKS: Water quantity, flood defence, drainage, environmental protection, maintenance.

FINANCING: Local taxes, subsidies from municipalities and provinces for maintenance, compulsory landowners’ fees, central government subsidy for investment in major projects.

Polders and “wateringen” are among the oldest and most characteristic public authorities in Flanders. The first watering is mentioned in 1183. According to legislation, their task has been to protect their management areas from water surpluses and assure a favourable water regime and hygienic conditions for agriculture. Agriculture have always been one of the main interests of polders and “wateringen”.

Today, they focus on integrated water resources management, which also includes nature protection, fisheries, tourism and drinking water supply. At present, there are 63 polders and “wateringen” covering a total area of 326.391 hectares.

Polders and “wateringen” are functional democracies. Stakeholders bear the costs through taxation and have a say in the assembly. This is the triple ‘interest-pay-say’ system.

2) FRANCE

Association Syndicales Autorisées (ASA)

STAKEHOLDERS IN BOARD: Cities, regions, union for marshlands, chamber of agriculture, landowners.

TASKS: Water quantity, flood defence, maintenance. FINANCING: Local taxes.

Depending on the region, the ASA member are responsible for managing excesses of water, river management, gravity irrigation, drinking water and erosion control in vineyard areas. The regulations governing these water authorities were laid down in the Order of 1 July 2004 and the Decree of 3 May 2006, which have replaced the 1865 law and its application decree. Water authorities have to act according to the environmental code for water management, updated in late 2006.

Of the 7,000 ASAs around the country, 4,000 are water boards. The others are responsible for other activities, such as road and infrastructure in forests and open

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countryside. More specifically, ASA members, address following tasks: managing excess of water (known as “wateringues”, they are more than 1200), responsibility for riverbank maintenance (200), responsibility for drinking water networks (140), construction and maintenance of erosion and flood control works in vineyard areas (50). More than 2.000 ASAs manage irrigation, half of them with gravitation canals, the other half with pumping stations and a network of pipes and tubes.

3) GERMANY

Deutscher Bund der verbandlichen Wasserwirtschaft (DBVW)

NUMBER OF MEMBERS: 1850.

STAKEHOLDERS IN BOARD: Landowners and tenants, municipalities.

TASKS: Water quantity, flood defence, maintenance, drinking water, wastewater treatment.

FINANCING: Taxation, fees (drinking water, wastewater treatment).

In 2000, 8 regional associations of water management organisations formed the German Confederation of Associational Water Management (Deutscher Bund der verbandlichen

Wasserwirtschaft) as a registered association to represent the interests of the associational

model at the federal level and, increasingly, at a European level. These associations represent the following regions: Schleswig-Holstein, Mecklenburg-Western Pomerania, Lower Saxony, Bremen, Saxony-Anhalt, Brandenburg, Hesse and Rhineland-Palatinate. The members, as decentralised public corporations, are municipalities or owners and users, or a mixed form combining these stakeholders.

4) HUNGARY

Vízgazdálkodási Társulatok Országos Szövetsége (VTOSZ)

NUMBER OF MEMBERS: 82.

STAKEHOLDERS IN BOARD: Farmers, municipalities, cooperatives. TASKS: Water quantity, flood defence, irrigation, drainage, maintenance. FINANCING: Taxation, fees (drinking water, wastewater treatment).

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VTOSZ was established in 1992. It functions as a spokesperson, service provider and employers’ federation for its members. The members of the VTOSZ cover the whole country. In total, there are 82 regional water authorities in Hungary. Their legal status is described in the 1995 Water Act.

Currently, members of the regional water authorities are farmers, municipalities and cooperatives. They pay a fee for the services delivered by water boards. In addition, the Ministry of Agriculture subsidizes the boards. A major challenge is to make the water authorities self-financing.

A relevant issue is due to the huge changes in property rights in the past (the transition from a command to a market economy): when land was given back to the original inhabitants by the state, a lot of land were not claimed. Therefore, water boards are still not able to derive incomes from these lands.

5) ITALY

Associazione Nazionale Bonifiche e Irrigazioni (ANBI)

NUMBER OF MEMBERS: 150 Consortia, 17.6 million hectares.

STAKEHOLDERS IN BOARD: Property owners (farms, industries. . .), municipalities. TASKS: Irrigation, drainage, flood defence, environmental protection, maintenance. FINANCING: Fees, based on services received.

Almost all drainage and irrigation boards (Consorzi di bonifica e irrigazione) in Italy are members of National Association of Consortia (Associazione Nazionale Bonifiche ed

Irrigazioni). ANBI safeguards the interests of the consortia at international, national and

local level and monitors proposals for legislation affecting them and their activities. ANBI advises the Consortia on legal, technical, fiscal, environmental, communication issues, etc. It also organises national and international conferences and workshops about drainage and irrigation. ANBI is an association, with private legal status.

6) PORTUGAL

Federação nacional de regantes de Portugal (FENAREG)

NUMBER OF MEMBERS: 28 Irrigation Associations covering 135,000 ha (76% of public irrigation).

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STAKEHOLDERS IN BOARD: Landowners’ organizations.

TASKS: Defend and promote the development of the irrigation sector, specifically the irrigation communities, develop the national economy, efficient water and energy use, and sustainable development.

FINANCING: Fees per area benefitting from irrigation.

FENAREG is a nationwide organization, founded in 2005, which aims to bring together the interests of stakeholders in activities related to water and water management and the agriculture and rural communities. FENAREG is a non-profit private association.

7) SPAIN

Federacion Nacional de Communidades de Regantes de España (FENACORE)

NUMBER OF MEMBERS: over 400 irrigators’ communities. STAKEHOLDERS IN BOARD: Landowners.

TASKS: Defending and promoting the development of the irrigation sector, developing the national economy, an efficient water and energy use, and pursuing sustainability. FINANCING: Fees per hectare benefitting from irrigation.

FENACORE is a non-profit association, founded in 1955, which brings together organisations dedicated to water management for irrigation, from surface or groundwater. It aims to combine the efforts and work of all those who work in the Spanish irrigation sector in order to defend their legitimate interests and rights to use water. It was involved in drafting the Spanish Water Act and its associated regulations (e.g. in relation to water prices), the National Hydrological Plan, and the National Irrigation Plan. Other important initiatives were the exemption of reservoir taxes and the electrical tax for irrigation and promoting the Water Framework Directive in Integrated Water Resources Management in river basins.

8) THE NEDERLANDS

Unie van Waterschappen (Dutch Water Authorities)

NUMBER OF MEMBERS: 22 regional water authorities.

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TASKS: Water quantity, flood defence, water quality, wastewater treatment, maintenance.

FINANCING: Taxes, fees, government subsidies.

Unie van Waterschappen, internationally known as Dutch Water Authorities, is an

international organisation comprising 22 regional water authorities in the Netherlands and their umbrella association, the Unie van Waterschappen. It promotes the interests of the regional water authorities at national and international level and shares a European office in Brussels with Vewin, the Dutch association of drinking water companies.

Local and regional water management in the Netherlands is largely the responsibility of regional water authorities, which are decentralised and financially self-sufficient public authorities. Regional water authorities are legally embedded in the overall democratic structure of the Netherlands.

9) UNITED KINGDOM

Association of Drainage Authorities (ADA)

NUMBER OF MEMBERS: 111 Internal Drainage Boards (IDBs), 13 regional flood and coastal committees, 3 national flood management authorities, municipalities and corporations.

STAKEHOLDERS IN BOARD: Landowners and tenants, municipalities.

TASKS: Water level management, flood risk management, irrigation, water and environmental quality and drainage channel and asset maintenance.

FINANCING: Local taxation, levies on municipalities, government and EU grants, partnership contributions.

ADA was established in 1937 to watch over and support the interests of drainage authorities at national and parliamentary level, providing a forum for the exchange of ideas and discussions, and disseminating information of common interests. ADA now has around 230 members, representing all forms of water level management authorities from England, Wales and Northern Ireland. It was a prime player in the formation, and a founder member of the European Flood Control and Water Level Management Associations.

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ADA itself is a company operating under limited guarantee, with a Board of Directors. Internal Drainage Boards operate under Act of Parliament to provide a flood risk management and water level management service. Their main interests lie in low-lying land areas, often at or below sea level. IDBs depend on close working relations with other flood risk management authorities, including the Environment Agency, which concentrates on the management of main rivers, sea and tidal defences, and local authorities, which manage all other watercourses, surface and groundwater.

1.4 Case studies

In the following paragraphs, we will provide an overview of two drainage authorities:

Consorzio di Bonifica 4 Vasso Valdarno (Italy) and Gdańskie Melioracje (Poland). It will

be useful in order to underline differences and similarities between the present situations in two UE members. In this Chapter, we will outline territories and structures. We will focus on the legislative frameworks in Par. 2.3.3 and on management issues in Par. 2.7.9. As introduction, we may say that the environmental and operative context in which these two authorities work is considerably different:

- The Italian board is characterised by a mainly agricultural land use and it is concerned of drainage an irrigation as well as flood protection of rural areas. - The Polish board, apart from similar agricultural issues, has to address urban

run-off and storm water tasks, since it provides services in an urban context as well.

1.4.1 Consorzio di Bonifica 4 Basso Valdarno (Italy)

The Consorzio di Bonifica 4 Basso Valdarno became operational in March 2014, after the sector reorganization performed by Tuscany Region [6]. It incorporates the areas of three former existing Consortia: Padule di Fucecchio, Val d’Era and Ufficio Fiumi e

Fossi. Its registered office is located in Pisa.

This board is an economic public corporation, administered by its members, and it is in charge of hydraulic defence, drainage, irrigation and environmental protection in the managed district. It has also a social relevance since it employs 83 people [7].

Fees from citizens finance consortium regular activities. Every citizen or legal person who owns immoveable properties (land or buildings) within the managed district and

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receive benefits from Consortium activities has to pay. Fees depend on the benefit gained by each member [8].

Managed territory

Consortium territory is 208,052 hectares wide and covers parts of five provinces (Pisa, Pistoia, Lucca, Leghorn, and Florence) and fifty-five municipalities are engaged. The most part (about 95%) is flatland. The inhabitants living in interested municipalities amount at 831,472. 249,356 of them are property owners and, consequently, pay fees to the Consortium. This data are updated at October 2014.

Figure 1 - Territory of Consorzio di Bonifica 4 Basso Valdarno

PISA

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Within his territory of competence, Consorzio di Bonifica 4 Basso Valdarno manages the minor hydrographic network (4,172 km long, 953 of which are embanked). Arno River Basin Authority (following the WFD [9] implementation it is now incorporated in the Autorità di Bacino Distrettuale dell’Appennino Settentrionale) is responsible for the most important water bodies (Arno River and Diversion Channel).

Several wetlands and Natura 2000 sites exist in this territory. Padule di Fucecchio, the Italian larger wetland in the inland, is of outstanding relevance. A LIFE+ Project was recently developed in these areas (“SOS Tuscan Wetlands Project”).

The management of Natura 2000 sites is different from all the other areas. Indeed, within these sites the Consortium regularly performs the ordinary maintenance (grass mowing . . .). The extraordinary maintenance is still performed by the Consortium, but it is designated and financed by Tuscany Region. Usually both the operations are performed and financed by the Consortium.

Managed water facilities

In the table below, we summarized the most important water facilities in this drainage district. Indeed the Consortium is responsible for a certain amount of mechanical and hydraulic facilities which guarantee a proper network functioning.

Unit Value

Total surface of CBV Territory ha 208,052

Managed drainage network km 4,172

Drainage pumping stations (number of plants, drainage surface, flow rate)

n. 23

ha 14,400

l/s 111,680

Flood control reservoirs [number, total surface]

n. 35

ha 270

Drainage facilities (weirs, sluices. . .) n. 1,702

Basins [number, total volume] n. 2

m3 _211,400

Levees km 953

Irrigation aqueduct n. 1

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1.4.2 Gdańskie Melioracje (Poland)

"Gdańskie Melioracje" is a municipal company established on 1 August 1993. The main objectives of the company are related to the City of Gdansk and its neighbouring areas through managing and maintenance: sewerage system, rainwater system (reservoirs, streams, canals and ditches), flood protection, and maintenance of fountains (including the historic ones).

In the case of Poland, most of the inhabitants do not pay for storm water management. Citizens of Gdansk are not an exception. This situation will change soon due to the introduction of further steps necessary to fulfil the Water Framework Directive [9] requirements. The first approach was in 2001 when new Polish Water Law was introduced. During the last fifteen years only amendments were done. Now intensive work on new Water Law have been undertaken and one of the most important issue is ensuring the return cost of water service. Among others, this will be achieved by introducing charges for storm water management.

Managed territory

Gdańskie Melioracje covers the territory of the City of Gdańsk and it is 262 km² wide

(see Fig. 2). The inhabitants living in interested municipalities are 460,354 (updated at 2012). Currently, in Gdańsk there are altogether 49 reservoirs with a total retention volume 678 826 m3 and a surface of 60.98 hectares.

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17 Managed water facilities

The water facilities of Gdańskie Melioracje reflect the variety of contexts in which it operates. Indeed, we may find urban retention tanks as well as, for example, drainage ditches. A summary of managed water facilities is outlined in Table 3.

Unit Value

Streams m 78,020

Primary drainage channels m 63,788

Drainage ditches m 168,095

Retention tanks

n. 48

m3 _576,795

ha 58

Retention volume of Lake Jasień [11] ha 577

Structures of water units n. 1098

Levees m 15658

Drainage pumping stations n. 8

l/s 4,670

Radunia river channel m 9,815

Vent water overflow Radunia channel n. 3

m3_/s _31.20

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2) ISSUES RELATED TO SEDIMENT

MANAGEMENT AND DRAINAGE NETWORKS

2.1 Introduction

Drainage network management belongs to the wider family of inland water management and shares similar issues related to sediments with it. Therefore, in the thesis we will make a general discussion about sediment issues with the aim of posing the basis for a tool to be implemented in all fresh water systems. We will focus on drainage network in chapter 4 and 5, applying our analyses in practice.

We focussed on freshwater sediment. Salt-water sediments further complicate the matter, both from the point of view of the management and from the point of view of remediation, since some remediation technologies are negatively affected by salt.

2.2 Sediments and related environmental issues

2.2.1 What sediments are

Sediments are an essential, integral and dynamic part of our river basins. In natural and agricultural basins, sediments are derived from the weathering and erosion of minerals, organic material and soils in upstream areas and from the erosion of riverbanks and other in-stream sources. Then, they are transported in river systems in the direction of the coast, with oceans being the final sink [12].

Sedimentation is a natural process and represents a fundamental part of ecosystem functioning [13]. As surface-water flow rates decline in lowland areas, transported sediments settle along the riverbed and banks by sedimentation. It occurs also on floodplains during flooding, in reservoirs and lakes. Often the natural sedimentation areas are severely restricted and sediments are trapped behind dams, hence reducing the supply

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of sediment downstream. Important impacted areas downstream are wetlands, deltas and harbours [12].

At the end of most rivers, the majority of the remaining sediments is deposited within the estuary and in the coastal zone. Mixing of fluvial and marine sediment occurs in estuaries, where sediments are transported both downstream and upstream because of tidal currents. Natural river hydrodynamics maintain a dynamic equilibrium, regulating small variations in water-flow and sedimentation by re-suspension and resettlement. In the river system, temporary deposition may take place. Important in this respect are floodplains and lakes [12].

It is clear that a combination of several factors (land use, climate, hydrology, geology and topography) determines the amount and timing of sediment delivery to rivers [12].

The value of sediments

Sediment forms a variety of habitats that host many aquatic species. Microbial processes cause regeneration of nutrients and important functioning of nutrient cycles for the whole water body. Sediment dynamics and gradients (wet-dry and fresh-salt) form favourable conditions for a large biodiversity, from the origin of the river to the coastal zone. Clean sediment is a key point for water life. Sediment is also a resource for human needs. For millennia, humankind has utilised it in river systems as fertile farmland and as a source of construction material [12]. Even if sediments are polluted, they may be resources by means of beneficial use after proper remediation treatments.

2.2.2 Typologies of sediments analysed in this thesis

Sediments from streams or drainage canals and ditches

Drainage canals and ditches mediate the flow of pollutants from agroecosystems to downstream water bodies and provide a unique opportunity to address nonpoint source pollution issues from agriculture due to the concentration of the contaminants and the engineered nature of ditch systems [2]. Because of the flow conditions of drainage water, transport capacity reduces and sediments are deposited; these settlings tend to accumulate various types of substances and to be often characterised by non-acceptable levels of contamination [14].

Since drainage networks are mainly located in rural areas, they are affected by contaminants coming from agricultural activities. Nevertheless, increased concentrations

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of nutrients and heavy metals may be found in sediment of drainage canals that run near major urban areas and industrial facilities. Indeed, in addition to their main drainage function, these canals became recipients of untreated, highly contaminated municipal and industrial wastewaters. This sediment may pose serious environmental problems, affecting not only the canals themselves but their surroundings as well [14]. Stream and river sediment shares similar concerns.

Most common contaminants in drainage networks are nutrients, hydrocarbons, pesticides and heavy metals.

Sediments from urban storm water runoff

Many studies conducted in different countries have pointed out that storm water runoff from urban areas is highly contaminated and may have a negative impact on receiving water bodies [15]. Urban runoff is a relatively recent concern, but it is has become an important issue because of its potential effects on the ecological health of urban streams and coastal waters, as well as on the economic, social and cultural value of these environments. Storm water quality is closely linked to quality of sediments.

When rain falls or snow melts, the runoff washes pollutants off streets, parking lots, construction sites, industrial storage yards, and lawns. Urban runoff carries a mixture of pollutants from our cars and trucks, outdoor storage piles, muddy construction sites and pesticide spills. Efficient systems of ditches, gutters and storm sewers carry the polluted runoff to nearby lakes and streams, bypassing wastewater treatment systems [16]. Storm water coming from streets and parking lots contains hydrocarbons, oils and grease, lead compounds from engines, and salts used for snow and ice removal from the streets [15].

The characteristic features of storm water runoff are fluctuating quantity and composition dependence, among others, on intensity and frequency of storm events and the type of catchment area. [15]

Since urban areas have more impervious surfaces than rural ones, more water runs off unfiltered by soil or vegetation, instead of soaking in. Cities may have less soil erosion than rural areas, but urban areas produce their own distinctive mix of sediments: flakes of metal from rusting vehicles, particles from vehicle exhaust, bits of tires and brake linings, chunks of pavement, street rubbish, remains of erosion, incombustible leavings of fuels and soot from residential chimneys as well as industrial smokestacks [15], [16]. Suspended solids in storm water are the most relevant point due to quite large loads of

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pollutants (organic matter, nutrients, heavy metals…) adsorbed on the particles’ surfaces. Types and quantities of pollutants depends on particle sizes [15].

The most contaminated is the first flush (about 20 min) of storm events, which may be even more polluted than municipal wastewater [15], [17], [18].

Damming and reservoir sediments

Damming has provided huge benefits to agriculture, industry and urban development. The report of the World Commission on Dams (2000) has highlighted that dams, inter-basin transfers and water withdrawals for irrigation have fragmented over 60% of the world’s rivers and changed the sediment load of rivers to the coastal sea. The greatest density of reservoirs in Europe is found in the Mediterranean basin (Spain, Italy and Greece) [12].

These reservoirs are human-made sediment traps: more than 90% of the sediment transport of incoming streams may be stored when the residence time of the water exceeds two months. Sediment trapping has a positive environmental effect for the protection of downstream areas because means contaminant trapping as well. However, it affects the hydrology and morphology of the river downstream. The decrease in sediment supply compels the riverbed to find a new equilibrium and also causes erosion in coastal zones, which affects coastal morphology. Resources like floodplains and wetlands are similarly affected [12].

Land use in the water catchment area influences sediment characteristics, thus determining levels and types of contamination.

2.2.3 Quantity related issues for freshwater sediments

Soil erosion and sediment yield are strongly influenced by geomorphology and use of soil. Erosion rates (sediment production) ranges from 100 t km-2 year-1, in humid environments of northern Europe, to 500 t km-2 year-1 in Mediterranean humid environments (mid-southern Europe), reaching a maximum of 2500 t km-2 year-1 in semiarid regions of southern Europe. It has been estimated a total amount of 1800 x 106 t km-2 year-1 of sediment delivered from land to rivers in Europe, not including bedload (i.e. coarse-grained sediment, which is likely to be between 10 and 20% of the total value, reaching the 50% in mountain areas) [19].

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Figure 3 - Sediment yield in European rivers (not including bedload) [20].

According to Walling and Webb (Figure 3) sediment yield ranges from 50 t km-2

year-1_{, in humid low relief environments, to 150 t km}-2_year-1_{in Mediterranean low relief}

environments, reaching a 500 t km-2_year-1_{in both humid and Mediterranean mountainous}

regions (e.g. Spanish and Italian coastal ranges, Pyrenees, Alps) [19].

While humans have increased the continental flux of sediments during the last two millennia, most of the land-derived erosional sediments remain stored somewhere between the uplands and the sea. Storage of sediment in large reservoirs constructed during the last 50 years has decreased the global flux of sediment to the coastal zones by 30% [21]. A relevant source of sediment, especially in agricultural landscapes is bank erosion. This phenomenon is often aggravated by agricultural practices. Indeed, it is a common habit to plough land near banks, increasing the amount of soil particles transported by run-off waters into water bodies.

Even if it is clean, sediment may have environmental and socio-economic impacts. For instance, turbidity and excessive sedimentation have a physical effect on benthic life, too much sediment in navigation channels requires costly dredging, and sedimentation behind dams decreases their economic lifetime. Furthermore, dams decrease the supply of sediments needed to support downstream wetlands, estuaries and other ecosystems, increasing the risk of soil and coastal erosion [12]. Hydromorphological pressures (changes to the physical shape of water bodies) affect many surface water bodies altering habitats. They are mainly the result of hydropower, navigation, agriculture, flood protection, and urban development [22].

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A major reason of concern about sediment quantity is its close relation with flood risk. An excessive sediment accumulation in streams unavoidably modifies the shape of cross-sections, reducing the area available for water flow. In case of unfavourable weather events, current cross-sections might be unable to contain such an amount of water, causing floods.

2.2.4 Quality related issues: sediment contamination

Introduction and up-to-date overview of European freshwater condition

The term ‘contamination’ means the introduction into environmental matrices (water, air, soil) of any substance, compound or agent in such concentrations to make that matrix not suitable for its actual or potential use [23]. Contamination has become a critical issue worldwide due to its great harm to the ecological environment and public health. A growing public concern is arising over the issue of soil and sediment contamination resulting from industrial and municipal waste discharge, mining activities, improper use of chemical fertilizer and pesticides, and wastewater irrigation [24].

More than half a million sites throughout the European Union are thought to be contaminated and, until they are identified and assessed, they will continue to pose potentially serious environmental, economic, social and health risks [25]. On the other hand, Europe is far from meeting water policy objectives and having healthy aquatic ecosystems [22].

Studies refer that rivers and transitional waters are on average in a worse condition than lakes and coastal waters. Concerns about the ecological status of surface water bodies are most pronounced for central and north-western Europe, in areas with intensive agricultural practices and high population densities. [22]

The main aim of European and national water policy is to obtain a sufficient quantity of good-quality water for people's needs and for the environment. In 2000, the Water Framework Directive [9] established a framework for the management, protection and improvement of the quality of water resources across the EU. Its main objective was obtaining ‘good status’ for all surface and groundwater by 2015. Achieving ‘good status’ means meeting certain standards for the ecology, chemistry, morphology and quantity of waters [22]. An overview of the ecological status of European water bodies is given in Figure 4.

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Figure 4 - Percentage of good ecological status or potential of classified rivers and lakes in WFD river basin districts [22, 26].

An important detail to be considered is that water quantity and quality are closely linked: a key element of meeting ‘good status’ standard is ensuring that there is no over-exploitation of water resources [27].

Chemical status is another cause for concern. Around 10% of European rivers and lakes are in poor chemical status, with polycyclic aromatic hydrocarbons a widespread cause of poor status in rivers, and heavy metals a significant contributor to poor status in rivers and lakes. Around 25% of groundwater has poor status (nitrate is the primary cause). There is still a lack of information about water bodies: the chemical status of 40% of Europe's surface waters remains unknown [22].

Excessive nutrient (nitrogen and phosphorus) inputs in aquatic environments are a major threaten. They cause eutrophication, resulting in changes in species abundance and diversity, as well as algal blooms, deoxygenated dead zones, and leaching of nitrate to groundwater. All of these changes threaten the long-term quality of aquatic environments, influencing the provision of ecosystem services such as drinking water, fisheries, and recreation opportunities [22].

Traditionally, we may distinguish between point and diffuse sources of pollution. A point source is a single, identifiable source of pollution, such as a pipe or a drain. Industrial wastes are commonly discharged to rivers and the sea in this way. Diffuse sources refer to those inputs and impacts that occur over a wide area and are not easily

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attributed to a single source. They are often associated with particular land uses [28]. We will examine other aspects of these concepts in the following pages.

Pollution from diffuse sources affects most surface water bodies. Agriculture is a particularly large source of diffuse pollution, causing nutrient enrichment from fertiliser run-off. Pesticides have also been widely detected in surface and groundwater bodies [22].

Europe's waters are much cleaner than they were some decade ago, due to the investment in sewage systems to reduce pollution from urban wastewater treatment. Nevertheless, more than 40% of rivers and coastal water bodies are affected by diffuse pollution from agriculture, while between 20% and 25% are subject to point source pollution, for example, from industrial facilities, sewage systems and wastewater treatment plants (see Fig. 5) [22].

Figure 5 - Percentage of classified rivers and lakes in Water Framework Directive river basin districts affected by pollution pressures [22, 26].

For what regards nutrient levels in freshwater bodies, they are decreasing. This mostly reflects improvements in wastewater treatment and reductions in the levels of phosphorus in detergents, rather than reductions in agricultural inputs of nitrate at European and national levels. Although farming nitrogen balances are declining, they are still high in some countries, particularly in lowland Western Europe [22].

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26 Sources and transport of contaminants

Contamination of water and sediment are strictly related by a two-way flow connection: polluted waters may influence sediment quality and vice versa. Sediment acts as a potential long-term sink for many hazardous pollutants [12, 29].

Due to their properties, many chemicals substances may stick to suspended particles, which might subsequently be deposited as sediment in stagnant areas. Hence, in areas with a long record of sedimentation, sediment cores reflect the history of the pollution in a given river basin. Where water quality is improving, the legacy of the past may still be present in sediment. It may become a secondary source of pollution when it is eroded (i.e. via bioturbation, dredging or during flood events) and transported further downstream [12, 29].

Contaminants enter the fresh water system through various pathways. A distinction may be made between rural areas, urban areas and direct inputs [12]:

- Input from rural areas is through erosion of soils, channel bank erosion, waste dumps and, indirectly, from atmospheric deposition on soils.

- Urban areas contribute through leaching from building material and from sewer systems.

- Direct inputs are derived, for example, from industry and shipping.

The following Figure 6 clarifies the interaction between various components acting in the overall system.

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Figure 6 - A generalised overview of land use and pathways of contaminants [12, 30, 31].

Soil and water contamination has a strong connection with land use. Every year more than 1 000 km2 of land are taken for housing, industry, transport or recreational purposes in Europe [25]. These new soil uses are substituting natural and semi-natural habitats as a part of a long-term phenomenon named as ‘Land take’. This substitution extends to

varying degrees the impervious cover, affecting the provision of important services provided by soils, such as the storing, filtering, and transforming of substances such as nutrients, contaminants, and water [22].

As abovementioned, a common distinction is between point and diffuse sources of pollution. This distinction reflects their behaviour under changing meteorological conditions [30]:

- Point sources are identifiable points that are fairly steady in flow and quality. The magnitude of pollution is not influenced by the magnitude of meteorological factors. Major point sources, under this definition, include municipal and industrial wastewater effluents.

- Diffuse sources are highly dynamic and widely spread pollution sources and their magnitude is closely related to meteorological factors such as precipitation. Major diffuse sources, under this definition, include surface runoff (load from atmospheric deposition), groundwater, erosion (load from eroded material), and diffuse loads of paved urban areas (atmospheric deposition, traffic, corrosion)

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including combined sewer overflows since these events occur discontinuously in time and are closely related to precipitation.

In Western Europe rivers, the contribution of point sources to total loads has decreased over the past decades: a reason for this are the efforts of industry in combating pollution discharge. As a result, the contribution from diffuse sources is becoming (relatively) more important [12].

Riverine material is characterised by a continuum of sizes from pebble to purely dissolved forms. Conventionally, we may distinguish between dissolved and particulate compounds. This distinction reflects in different behaviour [12].

- Dissolved compounds are that which passes a filter with a pore size of 0.45 µm. They are transferred across aquatic systems together with the water.

- Particulate compounds are that which does not pass a filter with a pore size of 0.45 µm. They may settle and be remobilised, according to flow velocity, particle size and shape, riverbed morphology, etc.

The fine and medium-sized particles (i.e. below 63 microns) are the most important. In fact, the properties of these fine particles (e.g. large specific surface areas, high ion exchange capacities) enable them to act as efficient scavengers of contaminants discharged into the river system [12].

Along the course of the stream to the sea, transportation, dilution and redistribution of sediment associated contaminants occurs. Many relatively small inputs, all complying with emission regulations, accumulate to reach higher levels by the time sediment reaches the river mouth. In the estuary, uncontaminated marine sediments are mixed with contaminated fluvial sediments. This natural ‘dilution’ decreases contamination level in a gradient towards the sea over short distances, but does not alter the actual transported quantity of contaminants [12].

The transport of contaminants is influenced by the flow rate of a river system. A significant example of this relation may be the cadmium concentration in the River Rhine (Fig. 7).