Title Deliverable: Diagnosis Report Gouda Wastewater Monitoring Network The

DC-Project code: DC Project Title: Integraal Stedelijk Waterbeheer CT06.20 DC-Work package code DC Work Package Title: Integrale pilot: Hoogwaterstad CT06.24.11

Principal Author 1: Carlos Vélez Institute: Principal Author 2: Ioana Popescu Institute:

Contributor 1: Arnold Lobbrecht Institute Contributor 2: Alberto Galvis Institute

Report Type: Final report Report Status: Definitief Number of pages: 45 Number of Annexes: Keywords (3-8): Urban Wastewater Systems, water quantity, water quality, advanced micorprocessors, hydroinformatics tools Abstract: Urban pollution managers are being forced to optimize the control of Urban Wastewater Systems (UWwS) in order to deal with more pressure and new criteria for performance. Furthermore, one of the main causes of the deficient control of the UWwSs is the lack of data in each subsystem and the lack of coordination within institutions to share the information and take decisions based on it. Even though, there are sensors available for water quantity and water quality, advanced microprocessors and hydroinformatics tools for information management, the lack of information is still one of the causes of the poor control of UWwSs. One way to tackle these problems is by defining clear and documented guide lines that allow the education institutions to fill the gab in the transfer of knowledge and technology to the practitioners in charge of design, operate and manage the UWwSs.

Institute Publication-number (optional): Isbn: Issn: DC-Publication-number (invullen door DC): CT06.24.R02

Date: 01-04-2008

Integrated Urban Wastewater System Data Network

Data.Net Project

Diagnosis Report Gouda Wastewater Monitoring Network The Netherlands

April 2008

ii Integrated Urban Wastewater System Data Network (DataNet Project)

Diagnosis Report Gouda Wastewater Monitoring Network The Netherlands

This document was elaborated by the Institute for water education of UNESCO-IHE in the framework of the “Integrated Urban Wastewater System Data Network - Data.Net Project.

The following professionals took part in the development of Data.Net Project

Institute for water education – UNESCO-IHE MSc Carlos Vélez PhD research fellow Dr. Ir Ioana Popescu Project Manager in Netherlands Dr. ir Arnold Lobbrecht RTC expert adviser

Universidad del Valle - Cinara Institute: MSc. Alberto Galvis Manager Project in Colombia Diana A. Cardona Engineer Paola A. Mosquera Engineer

This report was developed with the support of Rijnland Water Board and especial acknowledgement is given to the engineer Paul Versteeg and members of the board involved in monitoring and operation of the wastewater treatment plant of Gouda.

iii Table of Content

1 Introduction...... 1 2 Wastewater Monitoring Networks...... 2 2.1 Urban Wastewater Monitoring ...... 2 2.2 Information Flow in Urban Wastewater Systems...... 3 2.3 European Wastewater Monitoring Networks...... 4 2.4 Wastewater Monitoring Framework in The Netherlands ...... 5 3 Gouda Municipality ...... 10 3.1 Geographic location...... 10 3.2 Population and Density...... 10 3.3 Climatologic Conditions...... 11 3.4 Urban Wastewater Infrastructure and Institutions ...... 12 3.5 Water Plan of Gouda...... 13 4 Monitoring Network of Gouda Sewer System...... 14 4.1 Sewer System Description ...... 14 4.1.1 Sewer System Problems and Optimization Plan...... 15 4.2 Monitoring Network of Gouda Sewer System...... 16 4.2.1 Description of the Sewer monitoring program ...... 16 5 Monitoring Network of Gouda Wastewater Treatment Plant...... 19 5.1 Wastewater Treatment Plant Description ...... 19 5.2 Wastewater Treatment Plant Monitoring System...... 21 5.2.1 Description of the wastewater treatment plant monitoring program ...... 21 5.2.2 Wastewater treatment plant data processing and information flow...... 21 5.2.3 WwTP Data Validation, Filtration, Integration and Storage ...... 26 5.2.4 Analysis of the wastewater treatment plant monitoring system ...... 26 6 Monitoring Network of Hollandse Ijssel River ...... 28 6.1 Hollandse Ijssel Description ...... 28 6.1.1 River and other Inflows and Outflows ...... 29 6.2 Hollandse Ijssel Monitoring System...... 31 6.2.1 Description of the monitoring program ...... 31 6.2.2 Data Processing and Information Flow for Hollandse Ijssel River ...... 34 6.2.3 The Water Control Practice ...... 37 6.2.4 Analysis of the Hollandse Ijssel Monitoring System...... 38 7 Final Considerations ...... 39 8 References...... 41

iv 1 Introduction

Urban pollution managers are being forced to optimize the control of Urban Wastewater Systems (UWwS) in order to deal with more pressure and new criteria for performance. Furthermore, one of the main causes of the deficient control of the UWwSs is the lack of data in each subsystem and the lack of coordination within institutions to share the information and take decisions based on it. Even though, there are sensors available for water quantity and water quality, advanced microprocessors and hydroinformatics tools for information management, the lack of information is still one of the causes of the poor control of UWwSs. One way to tackle these problems is by defining clear and documented guide lines that allow the education institutions to fill the gab in the transfer of knowledge and technology to the practitioners in charge of design, operate and manage the UWwSs.

Thus the aim of Data Net project is to develop guidelines and educational material that can be used to fill the knowledge gaps in data acquisition and data exchange used to control UWwSs. The starting point of the project is the recover of experience in the field based in the diagnosis of two urban wastewater systems, one in Cali - Colombia and the other correspond to Gouda in the Netherlands. This report presents the results of the diagnosis of the existing monitoring networks for each component of the UWwS of Gouda.

The urban wastewater system was selected within the region of influence of Rijnland Water Board. In order to select the system 12 communities where analyzed and the Urban Wastewater System of Gouda was found as the must appropriated system to develop the research. From the institutional point of view is a system in which its optimization is of relevant interest to Rijnland Water Board and the Municipality. There is an interdisciplinary group confronting the problems of the system with an integrated vision, although the focus is more to optimize the performance of the sewer system, jointly measures are been considered. Within those prioritized measures the information is one on the top ten. The diagnosis of the monitoring system status includes an inventory of the UWwS components, and inventory of the existing monitoring networks focusing in answer the questions: who is in charge of monitoring?, what is measured?, where? And when?. Also the flow of information within the institutions is assessed considering how data is transmitted, quality controlled, stored, retrieved and used.

The diagnosis of Gouda, shows the need for increase the awareness of practitioners in advanced sensors for automatic monitoring of water quality gauges, improve the transmission of data to the operational level, improve the processing and generation of information useful for control purposes and the need for improve the sharing and integration of information from different institutions.

This report was developed with the support of Partnership for Water Education and Research (PoWER) in cooperation between the Institute for Water Education UNESCO-IHE and the Institute Cinara - Universidad del Valle. The project is a component of the research in Optimization of Urban Wastewater Systems using Model Based Design and Control (MoDeCo) in the framework of Cluster WP4.

1 2 Wastewater Monitoring Networks

2.1 Urban Wastewater Monitoring

Urban wastewater is defined as domestic wastewater or the mixture of domestic wastewater with industrial wastewater and / or stormwater run-off, according to the Council of the European Communities (CEC) Directive concerning urban wastewater treatment (CEC, 1991). The same directive requires from competent authorities monitor urban wastewater discharges to verify compliance of standards and monitor water receiving systems in cases where it can be expected that the environment will be significantly affected.

Different types of urban wastewater monitoring programmes can be implemented depending on the objectives (NZWERF, 2002): • Baseline monitoring: measuring the state of the receiving environment before commencement of discharge. This is often carried out as part of an Assessment of Effects on the Environment, and is usually more detailed than monitoring required under the resource consent conditions.

• Compliance monitoring: checking compliance with numeric limits in resource consent conditions from national or international obligations (usually discharge monitoring and/or receiving environment monitoring).

• Trend monitoring: documenting general trends over time in the characteristics of the receiving environment. This is usually not associated with resource consent compliance limits.

• Investigative monitoring: facilitating investigative monitoring that is activated on defined trigger- levels being exceeded, or when non-compliance occurs, to determine more precisely the nature and cause of the problem.

• Operational monitoring: added here to consider the need of monitoring to provide information for the business and operational needs of the regulators, suppliers, users and re-claimers of water.

With the implementation of the Water Framework Directive (WFD) an integrated management approach on catchment level is mandatory (CEC, 2000). Integrated urban wastewater management is an important part of the approach. One of the challenges is the integration of data collected in each component of the system (sewer network, wastewater treatment plants and water receiving system) in order to generate information useful for decision making at the urban catchment level. The WFD emphasises the need for monitoring networks designed to provide a coherent and comprehensive overview of ecological and chemical status within each river basin and enable the authorities to classify the water bodies. Three different types of monitoring programmes are defined by the WFD:

• Surveillance monitoring designed to provide information for supplementing and validating the impact assessment procedure, the efficient and effective design of future monitoring programmes, the assessment of long-term changes in natural conditions, and the assessment of long-term changes resulting from widespread anthropogenic activity.

• Operational monitoring designed to establish the status of those bodies identified as being at risk of failing to meet their environmental objectives, and assess any changes in the status of such bodies resulting from the programmes of measures.

• Investigative monitoring shall be carried out where surveillance monitoring indicates that the objectives set out for a body of water are not likely to be achieved and operational monitoring has 2 not already been established, in order to ascertain the causes of a water body or water bodies failing to achieve the environmental objectives, or to ascertain the magnitude and impacts of accidental pollution.

To cover the components of the urban wastewater systems and the objective of the monitoring programme, the wastewater monitoring networks have different types of stations: water quantity and water quality. Such stations provide different types of information for use by the authorities or management institution to meet the objective of the system. As defined by the European Environmental Agency (EEA) for surface water monitoring networks (EEA, 1996), such a structured monitoring network also imply that there is a need for different sample site densities, sampling frequencies and determinants for measurement . Thus, the wastewater monitoring network analysed in this report include the data acquisition, described by the location of the sampling stations, sampling frequency, variables measured and methods, and the utilization of information, described by data transmission, data storage, data analysis, generation of information and reporting procedures.

2.2 Information Flow in Urban Wastewater Systems

Lynggaard – Jensen (1999) describe the typical information flow in UWwSs (Figure 1). At the lowest level, sensor data are collected in data loggers or programmable logical controllers (PLCs) and transmitted to a Supervisory Control and Data Acquisition (SCADA) system main station. If the sensor data are only used for simple monitoring, time series may be displayed to the operators at this level; but if the sensor data are used for decision support or real time control, it is common to transmit these further on to a superior system, which uses the SCADA system as a front end. These superior systems are also more and more frequently connected to each other, if the monitored or controlled areas are connected in the real world (for example: sewer system and treatment plants in the same catchment area) giving the possibilities of exchanging data and information of preferred set points. Furthermore, these superior systems can be connected as information providers to the administrative level, giving condensed information to create an overview of the operative levels (Lynggaard-Jensen, 1999).

Figure 2.1. Typical Information Flow in UWwS Source: (Lynggaard-Jensen, 1999). 3

The automation of waste water systems (sewer systems and waste water treatment plants — municipal as well as industrial) is not as developed as other process industries mostly due to the very hostile environment where sensors have to be located. There has simply been a lack of proper sensors, which can be used for on-line real-time monitoring and control. However, recent years have shown use of classical sensors as pH, dissolved oxygen, redox, turbidity, etc, and the development and use of analyser systems for nutrients and organic matter have reached a level of practical use. Furthermore, new technologies are introduced, most of these using the real time calculation capabilities of microprocessors systems located directly in the sensors (Lynggaard-Jensen, 1999).

2.3 European Wastewater Monitoring Networks

The European Environment Agency (EEA) aims to support sustainable development and to help achieve significant and measurable improvement in Europe’s environment, through the provision of timely, targeted, relevant and reliable information to policymaking agents and the public. The European Environment Agency (EEA) has established, with its member countries, a monitoring network called Eionet Water (previously named Eurowaternet). Eionet Water is designed to give a representative assessment of the condition of water bodies and variations in human pressures within a country and across Europe. Information has been collected on:

• The status of Europe’s water resources, quality and quantity (status and trends assessments); • And how that relates and responds to pressures on the environment (cause-effect relationships).

The EEA bases its collection of water information on existing monitoring activities in member countries. A representative sub-sample of national monitoring sites in rivers, lakes and groundwater has been selected for the European network. Data are transferred on an annual basis from the countries to the EEA and stored in Waterbase. At the end of 2006, Waterbase contained information on more than 3500 river stations in 32 countries, more than 1500 lake stations, and quality data from around 1100 groundwater bodies.

Under the Water Framework Directive, Member States have to assess regularly the status of their waters. Part of their obligation under the Directive is therefore to establish a monitoring network in order to get a coherent and comprehensive overview of water status within each river basin district. In the future, the EEA monitoring network has to be adapted to meet the monitoring requirements of the WFD.

According to WFD (CEC, 2000), Member States shall ensure the establishment of programmes for the monitoring of water status in order to establish a coherent and comprehensive overview of water status within each river basin district: For surface waters such programmes shall cover: • the volume and level or rate of flow to the extent relevant for ecological and chemical status and ecological potential, and • the ecological and chemical status and ecological potential;

For groundwater such programmes shall cover monitoring of the chemical and quantitative status. For protected areas the above programmes shall be supplemented by those specifications contained in Community legislation under which the individual protected areas have been established.

These programmes shall be operational at the latest six years after the date of entry into force of this Directive (meaning 2006) unless otherwise specified in the legislation concerned. Technical

4 specifications and standardised methods for analysis and monitoring of water status shall be laid down in accordance with the procedure in Article 21 of WFD.

As analysed by Kristensen and Bøgestrand (1996), the majority of EU countries has national monitoring networks that collect information on water quantity and quality, however recently the member states had re-designed their monitoring networks to fulfil the needs of the WFD. To facilitate the process a Guidance Document denominated Monitoring under the Water Framework Directive was produced by Working Group 2.7 of the European Commission (EC, 2003).

In 2002, a partnership between the European Commission (DG Environment, Joint Research Centre and Eurostat) and the European Environment Agency (EEA) started the project denominated Water Information System for Europe (WISE). The partnership was committed to develop a comprehensive and shared European data and information management system for water by 2010. One of the first milestones achieved by WISE is the public web portal with wide information on a variety of European water related issues. All data displayed in the Water Information System for Europe (WISE) are reported by Member States or other countries reporting to the European Commission (EC) or the European Environment Agency (EEA). The data are reported in the context of the official reporting on the basis of EU legislation, in particular the Water Framework Directive (2000/60/EC), the Urban Waste Water Directive (91/271/EEC) or the Bathing Water Directive (76/160/EEC) or the data are submitted on a voluntary basis in the context of the EIONET agreements of the EEA (EEA, 2008).

Another important initiative was triggered by fragmentation of datasets and sources, gaps in availability, lack of harmonisation between datasets at different geographical scales and duplication of information collection. Thus, the European program Infrastructure for Spatial Information in Europe (INSPIRE) was established in 2004 and aims at providing a framework for the Spatial Data Infrastructure. The initiative intends to trigger the creation of a European spatial information infrastructure that delivers to the users integrated spatial information services. These services should allow the users to identify and access spatial or geographical information from a wide range of sources, from the local level to the global level, in an inter-operable way for a variety of uses. The target users of INSPIRE include policy-makers, planners and managers at European, national and local level and the citizens and their organisations. Possible services are the visualisation of information layers, overlay of information from different sources, spatial and temporal analysis, etc. The INSPIRE implementing rules were approved as the Directive 2007/2/EC of the European Parliament and of the Council of 14 March 2007 establishing an Infrastructure for Spatial Information in the European Community. The INSPIRE Directive entered into force on the 15th May 2007 and will be implemented in national legislation in the coming years (EC, 2008).

2.4 Wastewater Monitoring Framework in The Netherlands

The development of the sanitary infrastructure in The Netherlands started at the beginning of the 20 century with the construction of sewer networks (most of then combined sewers). By 1960 more than 80% of the households were connected to sewers, but the wastewater was discharge with out any treatment. In 1970 the wastewater treatment capacity was enhanced by the Pollution of Surface Waters Act (WVO Wet Verontreiniging Oppervlaktewater in Dutch). The Act provides the framework to control pollutants and gives the opportunity to provide further regulations. The law led to the construction of sewage treatment systems, the provision of discharge, the imposition of a licensing system on the discharge of sewage and standardisation on the discharges. By the end of 1980’s more than 90% of the household’s wastewater was treated (Langeveld, 2004)

The Netherlands has three levels of government: national, provincial and municipal. Each of these has its own range of duties within the relevant geographical area. The water policy is responsibility of the

5 Ministry of Transport, Public Works and Water Management at the national level and the 12 provinces at the regional level (Warmer and Dokkum, 2002). The main activities of the Ministry of Transport, Public Works and Water Management can be seen as a cycle of water management and policy, information need, information-gaining strategy, collecting information, processing information, and transferring information (Figure 2.2).

Figure 2.2. Information Cycle in Ministry of Transport, Public Works and Water Management Source: retrieved from www.Rijkswaterstaat.nl (January 2008).

The Ministry is responsible for the management of national waters. National surface waters are the main water (transport) system and include the rivers and (including sub-systems), Lake IJssel, estuaries, the Wadden Sea and the North Sea (Kristensen and Bøgestrand, 1996). Water management of national waters is delegated to the operational organization of the Ministry, the Directorate- General for Public Works and Water Management (Rijkswaterstaat in Dutch).

The provinces are responsible for the management of regional waters (small rivers and lakes, and the extensive system of canals and ditches) but they all have delegated this responsibility to 27 water boards. Water boards are (financially) independent of, but supervised by, provincial government. Until 1970 their main managerial responsibilities were related with water quantity i.e. flood protection, dikes, etc; but after 1970, when the Pollution of Surface Waters Act came into force their responsibilities extent to water quality issues. The water boards became responsible also for the treatment of urban wastewaters but excluding industrial wastewater. Industrial plants have to implement their own treatment facilities for the wastewater produced (Kristensen and Bøgestrand, 1996).

The municipalities are responsible for the provision, maintenance and operation of the sewers which convey wastewater to the urban wastewater treatment plants. In some cases the municipalities delegate the operation and maintenance of the sewer system to private companies.

Rijkswaterstaat has two water research and advisory bodies: RIZA (Institute for Inland Water Management and Wastewater Treatment) and RIKZ (Institute for Coast and Sea). RIZA and RIKZ have three main objectives: i) give advice on policy and management ii) gather information at the national level; surface water quantity and quality is monitored, partially analyzed at the RIZA laboratories, and the data is stored in information systems and used in reports on water trends and for policy development; and iii) coordinate water quality issues at a local level of government, through the CUWVO-coordination commission (Kristensen and Bøgestrand, 1996). A brief description of the main Dutch monitoring programmes is presented as follow.

6

The Water Monitoring System The water monitoring system (in Dutch Monitoring Systeem Water - MSW) produces continual information about the current level of the Dutch coastal and inland waters. Current speed and flow are also measured in the MSW. Using standard measuring apparatus, Rijkswaterstaat collects this information from over 160 locations. There are 25 locations in the national waters that constitute the discharge measuring network (the inflow and outflow points of the Netherlands, the important forks in the water systems and the points in the chemical measuring where loads are calculated). The water levels are continuously measured at 109 locations (of which 36 are on the large rivers, 12 on large lakes, 20 on tidal rivers and 41 along the coast at sea and in the estuaries). Information on waves and water temperature is also collected in the MSW monitoring network (Rijkswaterstaat, 2008).

The majority of the measurements are digital and 10 minutes average, with some exceptions where data is average up to 24 hours or in three stations where the reading is daily because is manual. The data are digitally available and stored in a central data base that can be consulted by government services, industry and public (see website www.actuelewaterdata.nl or www.waterbase.nl). The MSW provide among others information for: research and management of water in the country, bulletin services during storm flood and at extreme water levels on the rivers, the control of locks, operation of the dams, sluices and storm surge barriers, tidal predictions, exceedances frequencies of discharges and information for mathematical models (Rijkswaterstaat, 2008).

National Surface Water Monitoring Programme. The major part of water quality monitoring is encompassed by National Surface Water Monitoring Program (MWTL). The goal of this network is to test and detect trends in water quality. In 1955 chemical monitoring of inland waters was initiated at 4 locations. During the 1970s the number of locations increased significantly, during the 1980s, however, the number of locations decreased to about 130. In 1992 the monitoring network was evaluated and as a consequence of statistical relations between locations the number of locations was reduced to 26 and frequency increased. In addition to this re-design of the chemical monitoring, the biological monitoring network was started in 1992. Approximately 120 variables are measured and the water concentration is analyzed. Since organic micropollutants and metals are partially attached to suspended matter, some of these variables are also measured in suspended solids. The biological monitoring network in inland waters consists of the following groups: fish, birds, macroinvertebrates, zooplankton, phytoplankton, vegetation (water plants), and ecotoxicological variables. Some of the variables are measured yearly, as for other variables a four year monitoring cycle is set up according to which each year a water system is subject to detailed study (Kristensen and Bøgestrand, 1996).

Aqualarm The purpose of the Aqualarm monitoring network is early warning. Based on information on calamities, action can be taken and users of water warned. This network was initiated in 1974 and in the beginning of the 1990s (semi)continuous measurement of water quality was made at 7 on-line stations along the Rhine and the Meuse rivers. Since 1994 three stations remain (at the borders to Germany and Belgium along the rivers the Rhine and the Meuse and at Keizersveer).

At a national level polluted sediments constitute a major problem. For this reason (locally gathered) data on sediment pollution are reported by the CUWVO-coordination to RIZA and stored in an information system. On the basis of this information detailed studies are carried out, policy plans suggested and a clean up is initiated. The Table 1 shows the Dutch national monitoring programmes for surface waters.

7 Table 1. Dutch National Surface Water Monitoring Programmes Name Responsible Variables Period of operation Geographical Data & institution & Sampling coverage reporting Frequency (SF) Inland surface waters National Surface Water RIZA 120 chemical, Since 1955. SF: Presently 26 sites Data storage Monitoring Programme physical Chemical & physical throughout the and yearly (MWTL) and biological variables 6-52/yr, country reporting by variables biological variables RIZA 1-13/yr Aqualarm RIZA Chemical & Since 1974 7 online stations No reporting Early warning network physical (semi-) continuous along the rivers variables Rhine & Meuse Coastal and marine areas National Surface Water RIKZ Chemical, Since 1972. SF: 95 sites along the Data storage Monitoring Programme physical and chemical & physical coast and yearly (MWTL) biological variables 1-13/yr, reporting by variables biological variables RIKZ 1-18/yr Source: (Kristensen and Bøgestrand, 1996)

Local monitoring The monitoring network of local water boards operates at a regional level and is therefore not incorporated into the national programme. The regional monitoring network covers several thousands of locations. Network design and operation is coordinated by the CUWVO-commission (RIZA being the coordinator). To make an annual report on Dutch water quality, a nation-wide inventory on water quality data of representative locations has been set up by CUWVO. For next policy cycle the information is incorporated into the policy information system and the results of different policy scenarios are assessed. The water boards are also responsible to measure a number of wastewater treatment plant data according to the Dutch national standards. Yearly averaged data of individual wastewater treatment plants are published in reports. Statistics Netherlands collects these data and publishes average concentrations for the whole country.

Processing and transferring information Considering the large amount of information collected by Rijkswaterstaat and the water boards, in the early 1990s digital data storage and processing was introduced into water management. Rijkswaterstaat developed a central database denominated DONAR in which they store their monitoring information. Furthermore a dictionary called Omega was developed to ease the exchange of information (Lekkerkerk et al., 2007). In 1994, the water boards also developed their own information model denominated Logical Model Adventus in which the section related with monitoring data was based in DONAR data model. In 1997, the water boards, Rijkswaterstaat, the provinces, the ministry of Agriculture and Fishing and the Environmental Planning Agency signed a treaty on the exchange of information. The aim of the treaty was a further standardization of the information needed within water management, the exchange thereof as well as the joint development of datasets and information systems. Rijkswaterstaat in an effort to facilitate and enable access to data gathered as part of the water related activities, develop a Water Data Infrastructure (WADI) as a follow up of DONAR (Rijkswaterstaat, 2008). At the moment, an important part of the information, originated from the various monitoring programmes of Rijkswaterstaat and stored in DONAR, can be retrieved through a number of sites (see www.watermarkt.nl). In many cases, alongside the actual measurements, deduced, aggregated and modelled data are presented.

With the introduction of the WFD and INSPIRE, the interaction between water organizations and the need for integration and exchange of information have increased significantly. Thus, in 2003 the Information Desk standard Water (IDsW) was established. Its mission is to achieve an efficient and effective information exchange between water management organizations in the Netherlands. According to Lekkerkerk et al., (2007) a dual strategy was implemented to achieve this. First more 8 standardization of the information exchange and systems was needed. Second more interaction between the various organizations was deemed necessary, as well as the joint development of information systems and tools. To achieve it, the Adventus and the Information Standards of Commission on Integral Water management (CIW) as well as the Omega lexicon of Rijkswaterstaat were combined into the Aquo standard. This process resulted in a standard consisting of the following elements:

• Aquo-lex: water dictionary. • Aquo domain tables: lists of values (enumerations) used in information systems. • Logical Model Aquo (LMA): derived from the Adventus model. • Information Model Water (IMWA): a geographic exchange model.

As concluded by Lekkerkerk et al., (2007) the Netherlands are currently at the forefront of geo- information in and water management related information. But, there is still work to be done, especially with regard to the implementation of the exchange models and the development of methodologies and joint information systems such as the Aquo-kit. There is also the need to up date the internal efforts in exchange models with the WFD and INSPIRE directive. It is also possible to conclude from the review above presented that most of the effort has been done at the national and regional level, but much work have to be done at the local level. Improve the communication, data and information exchange and integration between urban wastewater managers is an important step in order to fulfil tight standards and limit pollution impacts.

9 3 Gouda Municipality

3.1 Geographic location

Gouda is a municipality locate in the western Netherlands, in the province of South . Gouda has border with three populations: in the North with , in the south-west with Moordrecht and Gouderak, and in the north-west with . Gouda takes its name from the Van der Goude family, who built a fortified castle alongside the banks of the Gouwe River. Around the year 1000, the area where Gouda now is located was swampy and covered with a peat forest, crossed by small creeks such as the Gouwe. The area, originally marshland, developed over the course of two centuries. By 1225, Gouwe was connected to the Oude Rijn (Old Rhine) by means of a canal that discharges in the Hollandse IJssel River. Nowadays Gouda cover 1,811 has and is divided in 13 districts, including a small community in south part of the city called Stolwijkersluis. Figure 3.1 shows the geographic location of the Gouda municipality and the distribution of its districts.

Waddinxveen Reeuwijk

Gouwe River Gouda

Stolwijkersluis

Hollandse Ijssel River

Moordrecht Gouderak Figure 3.1. Gouda Geographic Location and Districts Source: World Atlas.com, Google Earth and (Gemeente Gouda, 2006)

3.2 Population and Density

According to the Central Bureau for Statistics, Gouda has a population of 70,943 inhabitants by 2007, leaving in 29,997 houses. The population density in average is 39.2 inhab/ha being one of the most densely populated areas in The Netherlands. Figure 3.2 shows the growth pattern of the households in Gouda approaching its saturation value and Figure 3.3 shows the average population density per district. More detailed information of the population and density per district for 2007 is presented in Table 2.

10 35,000

30,000

25,000

20,000

15,000 Household 10,000

5,000

0 1940 1950 1960 1970 1980 1990 2000 2010 Year Figure 3.2. Number of Houses in Gouda (1945 to 2006). Source: (Gemeente Gouda, 2006) Central Bureau for Statistics

Figure 3.3. Average Number of Inhabitants by Hectare Source: (Gemeente Gouda, 2007)

Table 2. Population and Density per District Population Household Area Population Number District name Density Houses Density (ha) (inhabitans) (inhab/ha) (house/ha) 1 Binnenstad + Niewe Park 162 6485 40 3446 21.3 2 Korte Akkeren 195 9589 49.2 4054 20.8 3 Bloemendaal 278 9141 32.9 3953 14.2 4 Plaswijck 202 12922 64 5434 26.9 5 + Achterwillens 252 9930 39.4 4355 17.3 6 Kort + Oost 146 10517 72 4342 29.7 7 Goverwelle 150 11823 78.8 4200 28 8 Stolwijkersluis 94 412 4.4 159 1.7 Oostpolder in Schieland + 9 332 124 0.4 54 0.2 Westergouwe Total 1,811 70,943 39.2 29.997 16.6 Source: (Gemeente Gouda, 2007) Beheer Openbare Ruimte (geo-informatie) en afdeling Bouw- en Woningtoezicht, dienst Publiekszaken,CBS. Central Bureau for Statistics.

3.3 Climatologic Conditions

The predominant wind direction in the Netherlands is south-west, which causes a moderate maritime climate, with cool summers and mild winters. The Table 3 shows the mean measurements by Royal Dutch Meteorological Institute (KNMI in Ducht) weather station in between 1971 and 2000. Also are presented monthly precipitation in the Gouda station.

11 Table 3. Climatologic Conditions in Rotterdam and Gouda (1971 – 2000)

Station Parameter Unit Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Rotterdam Average Temperature oC 3.4 3.4 6.0 8.3 12.5 15.0 17.2 17.2 14.5 10.8 6.8 4.5 10.0 Rotterdam Average Minimum Temp oC 0.7 0.3 2.3 3.7 7.4 10.3 12.6 12.4 10.2 7.1 3.8 1.9 6.1 Rotterdam Average Maximum Temp oC 5.7 6.3 9.5 12.5 17.0 19.3 21.5 21.8 18.5 14.3 9.4 6.9 13.6 RotterdamAverage Relative Humidity%89868480788080808487888984 Rotterdam Average Precipitation mm 67.0 46.8 65.2 41.2 52.2 71.8 67.8 65.6 82.2 90.4 86.1 79.2 815.5 Rotterdam Average Wind Speed m/s 5.9 5.4 5.5 4.9 4.5 4.4 4.3 4.0 4.2 4.7 5.4 5.8 4.9 GOUDA Average Precipitation mm 66.8 48.0 67.8 44.3 55.4 75.1 71.1 63.7 78.0 84.2 85.7 80.2 820.3 Source: Koninklijk Nederlands Meteorologisch Instituut (KNMI, 2007).

3.4 Urban Wastewater Infrastructure and Institutions

The urban wastewater infrastructure of Gouda is composed by a sewer network and open canals, a wastewater treatment plant (WwTP) and the Hollandse Ijssel River as the main receiving system. The sewer network collects and transports domestic, commercial, treated industrial and in some of the areas where the system is combined, also storm water. The sewer network is responsibility of the Gouda Municipality, which is in charge of providing the service for the community and operate and maintain the system. An important network of canals drains the surface waters and functions as the main drain of storm water and combined sewer overflows (CSO). All the canals and the operational equipments (gates, pumps, etc) are responsibility of Rijnland Water Board. The wastewater treatment plant uses activated sludge processes to treat the wastewater of Gouda and some small communities around the city (Stolwijkersluis and Gouderak).

The WwTP is also responsibility of Rijnland Water Board. The final discharge of the wastewater from the city canals and CSOs or from the WwTP is the Hollandse Ijssel River, a branch of the Rijn Delta which is considered as part of the denominated national waters. The river is part of the important water networks for transportation because it connected to the North Sea through the Niuwe Maas River. Rijkswaterstaat is responsible for the Hollandse Ijssel River and its main tributaries (Gouwe River and canals). Regional divisions of the Rijkswaterstaat are in charge of the operation and control of the river. The subdivision of the wastewater management (Figure 3.4) implies also the subdivision of the monitoring networks in the system. In this water management arrangement, the need of interaction between institutions and the need for information exchange and integration is bigger if the sustainable wastewater management and the international obligations want to be fulfilled.

Waddinxveen Reeuwijk

Sewer System Gouda Municipality

Surface Water Canals Rijnland Water Board Rijnland De Stichtse Gouwe River Gouda Rijnlanden Schieland en de Stolwijkersluis

WwTP Rijnland Water Board Hollandse Ijssel Rijkswaterstaat River Moordrecht Gouderak Figure 3.4. Gouda Water and Wastewater Management Institutions Source: (Janse and Burgdorffer, 2005) and Google Earth

12 Due to the position of Gouda and the Hollandse Ijssel River, in addition to the Rijnland Water Board there are two more institutions involve in the water manage: De Stichtse Rijnlanden Water Board and Schieland en de Krimpenerwaard Water Board, both of interest for the management of Gouda water since they control tributaries of Hollandse Ijssel river.

3.5 Water Plan of Gouda

The municipality of Gouda with the Water Boards of Rijnland and Schieland and Krimpenerwaard developed a water plan (Gemeente Gouda et al., 2003). In the plan the vision has been described for the management of surface water and shallow groundwater in the municipality Gouda for the medium period (15-20 years). Main point is that on the long period (maximum 50 years) the whole sewer system has been converted into (improved) separate scheme. The water plan concerns especially with:

• Dry feet (occur of water nuisance): this part of the plan deal with the effect of extreme rainfall events and the need of the city related with flood protection. Thus more storage of rainwater is plan using large ponds and increasing the capacity of the existing open canals and the sewer system. • Healthy water (improve of water quality): it concerns the water quality of the surface water around Gouda. At the moment quality standards for phosphate, nitrogen, copper and zinc are especially exceeded. This comes as a consequence of the used construction materials and by the evacuation of environmentally unfriendly substances from roads and sewerage. In the future the plan goal is the compliance of WFD and the Dutch Maximum Admissible Risk (Maximaal Toelaatbaar Risico – MTR) norm. A large plan for reduce the pollution impact of the sewer system in the surface water have been put into practice. These plans have been set out in the municipal sewerage plan (Gemeentelijk Rioleringsplan - GRP) that it has been determined in 2004, by the municipality Council. • Speaking water (improve the perception of water): it concerns the contribution of water to the perception of the living, work and recreational surroundings. Water is generally very appreciated in the environment. In the old binnenstad of Gouda water is an indispensable element. Plans have been made for let children in a safe and playful manner get acquainted with water. • Work to water (make of mastering appointment): The municipality and the water board of Rijnland have made agreements concerning the maintenance of the water levels in the municipality. Furthermore by the Goudse Hengelaarsvereniging Viswaterpachting a fish mastering plan has been established, to which has contributed the municipality and the water board.

The water plan has conducted to a package of measures of different nature. Thus the plan also indicates the main principles of how the implementation of measures will be monitored. Much of the measures from the water plan have been meanwhile carried out or stand on planning. In 2007, an actualisation of the urban water plan was made. Also the new standards from the rural water policy 21st century and from the European framework directive water are involved.

13 4 Monitoring Network of Gouda Sewer System

4.1 Sewer System Description

Gouda Municipality is in charge of the sewer system. According to the Municipal Sewer Plan (Gemeentelijk Riolerings Plan - GRP 2004-2008 in Dutch) the city has 12 drainage areas, which are described in Table 4 and are delimited in Figure 4.1 (Gemeente Gouda, 2004). The type of sewer system is evolving from combined to separate scheme. Thus, it is possible to find five different schemes as is presented by the GRP of Gouda: • Combined Sewer: in this scheme domestic wastewater and storm water are collected and transported in the same pipe. Inline storage capacity is available. • Combined sewer surcharged: is a combined sewer scheme that is always full of wastewater and the wastewater have to drain out via an overflow or to other sewer mains. Since it is surcharged must of the time, it does not have inline storage volume available. • Separate Sewer: in this scheme, the domestic wastewater and storm water are collected and transported in different conduits. Before 2004, few areas of Gouda sewer system were uncoupled (area 9 named Oude Brugeweg and small part of area 4 named De Korte Akkeren). The trend is to uncouple the system into a separate sewer scheme. However the oldest part of the city, areas 5 Binnenstad West and area 6 Binnenstad Oost) will remain combined. • Improved Separate Sewer: in this scheme the storm water is exclusively transported and separated by a control system. The first part of run-off collected is removed to the wastewater treatment plant; the remaining part of storm water overflow to the surface water canals. According to the GRP, improved separate sewer exist in the area 11 named Oostpolder in Schieland and a small part of area 2 named J. van de Heijdenstraat. • Pressure Mains: Sewer where the transport takes place by means of pumps and press pipes.

Table 4. Drainage Areas of Gouda Sewer System. Area Pumps No Name Type sewer P.E. DWF WWF Capacity Storage * station

m3/h ha m3/h m3/h mm Combined Surcharge Combined Improved Separate Separate Pressure Mains 1 Bloemendaal x 26677 352 0 n.a. Bloemendaal 1080 n.a. J. van de J. van de 2 x x x x x 12968 213 75 507 720 3.1 Heijdenstraat Heijdenstraat 3 Achterwillens x 5589 73 8 227 Achterwillens 300 8.5 De Korte 257/ 4 x x x x 13423 200 86 Bosweg 3600 3.1 Akkeren 3337 Binnenstad 5 x 1641 29 16 131 Nieuwe Haven 150 4.6 West Binnenstad 6 x 3106 52 18 198 Tuinstraat 250 2.4 Oost F.W. 244/ 7 x x 11419 156 69 Reitzstraat 1800 4.0 Reizstraat 1262 Goverwelle Middenmolen 8a x 3156 40 0 n.a. 126 n.a. west laan Goverwelle Tempelpolder 8b x 5680 72 0 n.a. 252 n.a. Oost straat 10 Goudseweg x 310 4 0.7 16 Goudseweg 20 7.1 Oostpolder in 11 x 770 36 9 27 Edinsonstraat 63 3.0 Schieldand P.E: population equivalents. DWF: dry weather flow. WWF: wet weather flow. *: area drained by the sewer system. n.a:_no apply. Source: adapted with information from GRP Gouda 2004 -2008 (Gemeente Gouda, 2004).

14 Drainage Areas # Sewer Network Pumping Station Combined Sewer Overflow Storm Water Overflow Surface Water Combined Sewer System 1 Separate Sewer System Improved Separate Sewer 3 Pressure mains Separate Sewer (uncoupled)

2

5 7

8a 6 11 4 9 10 8b

WwTP

Figure 4.1. Overview of Sewer System of Gouda 2004. Source: GRP Gouda 2004 -2008 (Gemeente Gouda, 2004)

Gouda sewer system has 11 main pumping stations, one per drainage area as is indicated in the Table 4 and the location of them is showed in Figure 4.1. The main pumping station is named Bosweg (located in Area 4) and has an installed capacity of 3600 m3/h. Bosweg and Goudseweg stations pump the wastewater to the WwTP. In 2006 the maximum wastewater (domestic, commercial, industrial and stormwater) pumped to the treatment plant was 3300 m3/h (Gemeente Gouda, 2004). The sewer system also has 34 combined sewer overflows (CSOs) and 11 stormwater overflows that discharge mainly to the open surface waters (Figure 4.1). The open surface canals in the city are managed by Rijnland Water Board. Only the CSO of Bosweg discharge directly to the Hollandse Ijssel River managed by Rijkswaterstaat. Gouda municipality has delegated the operation and maintenance of the sewer system to the private company named Cyclus NV. Cyclus look after the daily operation of the system including 175 km of sewer, 200 large and small pump stations and 600 km of stormwater sewers (Cyclus NV, 2008).

4.1.1 Sewer System Problems and Optimization Plan Gouda has been built on peat and due to that, the ground sinks two centimetres per year. To reduce the risk of subsidence of the sewer, in the past, the municipality constructed the system behind houses (in small paths and backyards). However, the fact that the sewer lays down under private properties hampers the maintenance. The subsidence problem did not stop, and weakened pipes eventually fail creating as a consequence leaking and infiltration of groundwater and transport of soil and sand with the wastewater. The sewer scheme in the city centre (Binnenstad West and Binnenstad Oost) is very old and lies under the groundwater level. Every form of infiltration in the sewer pipes lead to a considerable groundwater level change. If the groundwater level in the city drops too low, the wooden foundations under the houses are affected (Gemeente Gouda, 2004).

15 Another problem arises during rainfall events when part of the combined wastewater overflows to open canals polluting the surface waters around the city. The water quality of surface water is assessed by comparing water quality data with the standards of the Maximum Admissible Risk (Maximaal Toelaatbaar Risico – MTR in Dutch) norm. This standardisation has been set out by Rijkswaterstaat and applies to all surface water in The Netherlands (Vierde Nota waterhuishouding, 1998). In the analysis of the wastewater impacts in the surface waters around Binnenstad of Gouda, presented by Tamboer (2007), the CSOs have an pollution impact in the water quality. Table 5 shows the percentile values of water quality measured in 2005 versus the MRT norm. As an example, this table shows that standards for Phosphorous, Nitrogen, Copper and Dissolved Oxygen (DO) are not compliant.

Table 5. Water Quality Values in Binnenstad Gouda Compared with MRT Norm for 2005 Phosphorous* < MTR Nitrogen* < MTR Copper < MTR DO > MTR Monitoring 90-perc 90-perc 90-perc 100-perc Point mg/l mg/l mg/l mg/l ug/l ug/l mg/l mg/l RO148 0.62 0.15 2.35 2.20 3.6 3.8 3 5 RO434 0.41 0.15 4.15 2.20 6.0 3.8 4 5 RO581 0.42 0.15 3.70 2.20 4.6 3.8 4 5 Average 0.48 0.15 3.40 2.20 4.7 3.8 4 5 * Summer Values. Source: (Tamboer, 2007)

In the Municipal Sewer Plan of Gouda GRP 2004-2008, a plan to address all this problems have been set up, and it includes: stabilize sewer pipes, uncouple the combined sewer system, reduce the infiltration by changing weakened pipes, build sewer in public areas to facilitate the access for operation and maintenance and connections by house. The new sewerage is planning to be a separate system or improved separated system. In addition to the separate system, drainage canals will be constructed in a way that allow to control the ground water level, via infiltration of rain water or discharge to surface waters to avoid problems in the foundations of the houses. The GRP plan last till 2030, so the replace and uncoupling of pipes will be done step by step to avoid greater nuisance to the community of Gouda (Gemeente Gouda, 2004).

4.2 Monitoring Network of Gouda Sewer System

4.2.1 Description of the Sewer monitoring program At the inventory stage of the water plan of Gouda was discovered some limitations in the knowledge concerning the functioning of the water system, both in terms of water quantity as well as water quality. One of the first actions in the water plan was completing the current gaps in the knowledge of the system. About water quantity for example there was the need to measuring the inflows to the water system and the evacuation flows. Furthermore, the need for measuring water quality issues as for example, estimating the influence of the sewer system on the surface and ground water quality and identifying ecological condition of the water ways and banks. In 2000-2001 as first step on a number of locations (monitoring points) physicochemical and biological measurings were performed. Also in 2001 a quick ecological assessment was done on these locations, completed with 18 locations in water ways elsewhere in the municipality. In that assessment the planning of the water ways and the ecological situation of water ways and banks was globally stipulated. These measurings together give an overall indication of current quality of the water ways and banks in Gouda and forms the actual situation (so-called zero situation) for the first plan period (Gemeente Gouda et al., 2003).

16 The monitoring programme of the Water Plan continues serving as a key element in the assessment of the measures carried out per each plan period (5 years). The monitoring plan executed in 2008 is show in the Table 6 and Table 7. Samples are collected in the monitoring points are the water quality parameters are analysed in the labs of Rijnland water board.

Table 6. Monitoring plan based in the Water Plan of Gouda for 2008 Type Code Description X-coord Y-coord Monitoring* ROP01116 Bloemendaal: Gouda from the bridge by Stolpenburg 108392 449676 N - M ROP16301 Willens: Pump 109419 447580 N – M RO581 Fluwelensingel by Pump Hanepraai 108908 446784 N – M ROP16304 Polder Willens: high site of dam de Willenskade 111540 446780 N – M ROP24501 Korte Akkere Pump 107191 447006 N – M RO116 Gouwe: at the Boezemgemaal Pump Gouda 107544 446025 N – M RO148 Breevaart: at bridge in Oostboezemkade Gouda 109296 448013 N – M RO434 Turfmarktgracht: at pump Mallegat Gouda 108564 446689 N – M RO874 WaterPlan Gouda - - N – M Polder Bloemendaal: NW Gouwe-O zijde ROP01117 107099 447661 N overkluizing gar. Huiden ROP16305 Willens: waterspeelplaats Zaagmolenpad - Sportlaan 110769 447082 N ROP16306 Willens: from bridge compared with Leenmanslag 41 109637 448652 N ROP01118 Waterplan Gouda - - N ROP01119 Waterplan Gouda - - N ROP01120 Waterplan Gouda - - N ROP01121 Waterplan Gouda - - N ROP16307 Waterplan Gouda - - N ROP16308 Waterplan Gouda - - N ROP24503 Waterplan Gouda - - N Source: (Hoogheemraadschap van Rijnland, 2008)

Table 7. Overview of Monitoring Parameters included in Water Plan Gouda 2008 Parameter Frequency Nutrients Nutrients and Metals Turbidity 12/year N N-M Visibility Depth 12/year N Steekbemonstering OW 12/year N N-M Temperature 12/year N N-M pH 12/year N N-M DO 12/year N N-M Ammonium – N 12/year N N-M Bicarbonate 12/year N N-M BOD 12/year N N-M Chloride 12/year N N-M Total Phosphorous 12/year N N-M Total Nitrogen 12/year N N-M Suspended Sediments 6/year N-M Phosphate – P 12/year N N-M Organic Nitrogen 12/year N N-M Sulphate 12/year N N-M Copper 6/year N-M Nickel 6/year N-M Zink 6/year N-M Chlorophyll a 12/year N N-M Pheophytin a 12/year N N-M Chlorophyll a Filtrated 12/year N N-M Source: (Hoogheemraadschap van Rijnland, 2008)

Additional information of the monitoring of the Gouda sewer system impacts in the water quality is presented by Tamboer (2007). In the document a water balance and an analysis of the pollution 17 impacts of the sewer discharge in the surface waters in the old part of the Gouda denominated Binnenstad is show in the Table 8. The information in the table complement the information from the Water Plan of Gouda and the Figure 4.2 shows the location of some monitoring points. Unfortunately there was not possible to establish cooperation with the Municipality of Gouda or with Cyclus NV to obtain information on the monitoring system limiting the diagnosis to the available documents on internet and at Rijnland water board. Table 8. Monitoring Points at Binnenstad Gouda Nr Code Description Period Frequency From To Via Reeuwijkse Inlaat polder 1 RO148 Breevaart 1969-2006 12/year Singel Plassen Reeuwijk 2 RO434 Turfmarkgracht 1987-2006 12/year Singel Hollandse IJssel Gemaal Mallegat Gemaal 3 RO581 Fluwelensingel 1998-2006 12/year Singel Hollandse IJssel Hanepraai 4 Zeugstraat Zeugstraat 1980-2006 365/year Binnengracht Singel Binnengouwe 5 Achter de Kerk Achter Sint Jan 1980-2006 365/year Binnengracht Singel Binnengouwe 6 Peperstraat Peperstraatgracht 1980-2006 365/year Binnengracht Singel Gouwe bij 7 C008 boezemgemaal 1970-2006 12/year Gouwe Singel KvL-sluis Gouda Hollandse IJssel Mallegatsluis, Hollandse Singel en 8 RO116 bij boezemgemaal 1959-2006 12/year Volmolenduikers, IJssel binnengrachten Gouda inlaat Havensluis Source: (Tamboer, 2007)

Figure 4.2. Location of Monitoring Points at Binnenstad Gouda. Source: (Tamboer, 2007)

According to (Blois, 2007), the municipality of Gouda have a telemetry system on the basis of monitoring on two locations that help to control in real time the pumping stations of the Sewer System. Due to the lack of information there was not possible to do an analysis of the monitoring network of the sewer system. Based in the information collected it can be inferred that the monitoring network of the sewer is as in many other cities in the world under developed, with few monitoring points and low frequencies in terms of water quantity and even less developed in water quality monitoring.

18 5 Monitoring Network of Gouda Wastewater Treatment Plant

5.1 Wastewater Treatment Plant Description

The Wastewater treatment plant (WwTP) of Gouda was built in 1976 and optimized in 1999 to its present state. Rijnland Water Board is in charged of the management of the system. The plant is designed for removal of organic matter, nitrogen and phosphorus from domestic and industrial waste water of Gouda and two small communities nearby Gouderak and Stolwijkersluis. The total plant loading design capacity is 140000 Population Equivalents (PE) and the hydraulic capacity is 4350 m3/h. The process includes primary treatment consisting in screens; the grid is removed from the first compartment of a selector composed by four compartments. After the selector water flow to an anaerobic tank (phosphorous release zone) composed by five compartments. Following, process have two activated sludge tanks, each consisting of one inner non aerated compartment (denitrification zone - anoxic) and an outer aerated compartment (nitrification zone - aerobic). After nitrification the wastewater is conducted to four secondary settlers. The phosphorus removal is achieved only using the biological process, even though there is the possibility to do chemical removal of phosphorus, that process is not used. The sludge is treated in a bio-digester and dewatering in belt filter press thickeners, the solids are incinerated out of the wastewater treatment plant and finally disposed. The treated wastewater is discharged into the Hollandse Ijssel River.

Figure 5.1 shows a plant view of the wastewater treatment plant and its components. There are three additional tanks in the picture that were trickling filters used before the optimization of 1999, but at the moment those tanks are not used in the treatment process. Table 9 shows water quantity and quality characteristics of the Gouda WwTP. The data are part of the annual report presented by Rijnland Water Board to Rijkswaterstaat institution from the Provincial level in charge of the control of inland waters. Table 9. Wastewater Treatment Plant Performance Designed Reported Value Effluent Parameter Unit 1999 2002 2004 2006 Standards Plant Loading P.E. 140000 95400 96200 100300 -- Hydraulic Capacity Average Flow m3/h 955 968 928 -- Max Flow m3/h 4350 3300 -- Influent Quality i BOD5 mg/l 155 142 139 -- COD mg/l 383 371 425 -- N-Kieldhal mg/l 40 39 41 -- P-Total mg/l 5.8 6.1 6.8 -- Suspended Solids mg/l 112 98 130 -- Effluent Quality i BOD5 mg/l 2 2 2 20 COD mg/l 32 33 34 No standards N-Kieldhal mg/l 2.6 2.8 1.9 20 P-Total mg/l 0.24 0.4 0.32 1 N-Total mg/l 7.9 7.2 7.0 10 Suspended Solids mg/l 3 3 2 30 Note: average values. – Do not apply. Source: Rijnland Water Board.

In terms of capacity the plant loading function with 30% less than the capacity for it was designed. In terms of hydraulic capacity the maximum flow is also not reached during wet season. That open room for optimization considerations using that hydraulic capacity available as is pointed out in the document Option of Optimization of the UWwS of Gouda (Langeveld and Jong, 2007). In terms of removal of pollutants the system is in average very efficient with values over 90% with exception of N-Total that is around 80% but still always fulfilling the standards. 19

6 6 4 River 5 5 Hollandse Ijssel 2 3 10

9

7 13 7 9 12 11

8 1

Item Component Unit/Compart Volume (m3) Item Component Unit/Compart 1 Gouda Pump station 3600 m3/h 8 Efluent Discharge 1 2 Screens 2 9 Sludge Pumps 4 3 Bulking Selector 4 688 10 Sludge Anaerobi Digester 1 4 Anaerobic Tank (P release) 5 4,812 11 Belt Filter Press 1 5 Anoxic Compartment (Denitrif) 2 5,028 12 Solid Loading Carrousel 1 6 Aerated Compartment (Nitrif) 2 24,096 13 Thickling filters (out of use) 3 7 Secundary Settlers 4 4,155 Figure 5.1. Layout of Gouda Wastewater Treatment Plant Image Source: retrieved from Google Earth January 2008. 20 5.2 Wastewater Treatment Plant Monitoring System

5.2.1 Description of the wastewater treatment plant monitoring program There are three types of monitoring process in the wastewater treatment plants. There is a manual sampling with basic operational parameters measured in the wastewater treatment laboratory, the second type is an on-line monitoring system that measure parameters and status of control elements for a supervisory control application and the third one is a performance monitoring based in influent and effluent quantity and quality with an automatic sampling equipment proportional to the flow, the water quality parameters are measured in the Lab of Rijnland Water Board. A characterization of each monitoring program is presented in Table 10.

5.2.2 Wastewater treatment plant data processing and information flow Each of the three types of monitoring programmes has its own data process, and the information flow differ also depending on the purpose of the data collected. Thus, following a description for each type of monitoring is presented.

The type I monitoring has as objective to verify that the system is performing well in terms of nutrient concentration in the effluent (NH4, NO3 and PO4) and the activated sludge process as the core of the systems is working properly (Suspended solids, oxygen dissolved and sludge settleability). The data is measured in the laboratory of the wastewater treatment plant (Figure 5.2) by the operator and the value is initially written down in a paper format (Figure 5.2). At this level data is used for the operator to judge the status of the WwTP operation. Every week data is digitalized and sent to the data base of Rijnland Water Board, however the data collected through this type of monitoring is not included in any report. The basic reason for that is that the water board does not consider the results obtained in the lab of the wastewater plant reliable enough to be used for report purposes.

Figure 5.2. Wastewater Treatment Lab and Operational Data Format.

The Type II monitoring program has as objective the automatic control (operation) of the system and generation of information for performance indicators. The data collection is based in on-line measurements of quantity and quality parameters and control elements. The WwTP has sensors located in various components (Table 10) and the data is transmitted to data loggers some of them display the instant values facilitating the visualization of the parameters to the operator on the field (Figure 5.3). The plant has a data transmission system that pass the data measured to a control unit room whit Programmable Logic Controllers (PLCs) (Figure 5.4). From there data flow to the central computer in the operational room (Figure 5.5), and from there again the transmission system help to transmit data to different devices (actuators).

21 Table 10. Monitoring of Wastewater Treatment Plant Sampling Sampling Type Responsible Parameter Unit Starting Frequency Storage Reporting/Use Place Method Influent On-line m3/d Flow Digitalized No report. and send Used for Effluent NH4 mg/l 1999 120/Year to RWB- effluent Manual + NO mg/l WwTP Lab 3 DB2 control PO mg/l I Operator 4 Suspended g/l Digitalized No report. Solids Aerated Manual + and send Used for Sludge 1999 120/Year Compartment WwTP Lab Index to RWB- operational Settleability DB2 purposes DO mg/l Flow m3/h Store Instant Annual Report Influent On-line 1999 locally and Temperature oC Measures and Operation RWB-DB DO mg/l Used for air Store Aerated Temperature oC Instant supply control On-line 1999 locally and Compartment Suspended Measures and sludge g/l RWB-DB solids production Pressure Bar Store Blowers Instant Used for air On-line 1999 locally and (air supply) Air Flow m3/h Measures supply control Automatic RWB-DB II System Sludge Flow m3/h Used for return Sludge Store Instant sludge and Return On-line Suspended 1999 locally and g/l Measures dewatering Pumps solids RWB-DB control Chemical - Level Used for Belt Filter Store Polymer Instant chemical Press On-line % 1999 locally and concentration Measures dosage in (Dewatering) RWB-DB Polymer dewatering l/h Flow On-line Flow m3/d BOD mg/l Automatic Annual Report COD mg/l flow to the Influent N-Kjeldhal mg/l 1999 52/Year RWB-DB proportional Provincial sampling + P-Total mg/l Level Suspended RWB Lab mg/l Solids BOD mg/l COD mg/l N-Kjeldhal mg/l Annual Report NO mg/l to the 3 1999 120/Year RWB-DB N-Total mg/l Provincial P-Total mg/l Level and CBS Operator + Suspended Rijnland mg/l Solids III Water Board Lab Arsenic µg/l Automatic Cadmium µg/l 1999 4/year flow Mercury µg/l Effluent proportional Silver µg/l Annual Report sampling + Chrome µg/l to the RWB Lab Copper µg/l RWB-DB Provincial 1999 20/year Lead µg/l Level and CBS Nickel µg/l Zink µg/l Barium µg/l 1999 30/year Strontium µg/l Annual Report 33 Organic to the Micro ng/l 1999 4/year RWB-DB Provincial Pollutants1 Level and CBS 1 Organic Micro-pollutants: P.A.K.-total, Benzo(B)fluorantheen, Benzo(K)fluorantheen, Benzo(G,H,I)peryleen, Benzo(A) pyrene, Fluorantheen, Indeno(123CD) pyren, Acenaftheen, Acenaftyleen, Anthraceen, Benzo(A)anthraceen, Chrysen, Dibenzo(A,H)anthraceen, Fenantreen, Fluoreen, Naphthalene, Pyren, pcb-28, pcb52, pcb-101, pcb-118, pcb-138, pcb-153, pcb-180, MO-GC, EOX, AOX als CL, Benzene, Ethbenzene, Toluene, Xylem, VOX, Meta and Para xylem, Ortho-xylem. 2. RWB-DB: Rijnland Water Board Data Base 22

Figure 5.3. Examples of Data Logger (left) and Air Flow Meter (right)

Figure 5.4. Central Control Units Room (left) and Programmable Logic Controller (right)

Figure 5.5. Operator Console (SCADA GUI) Thus the Supervisory Control And Data Acquisition (SCADA) system is fully conformed and on top of it the treatment plant has a real time control algorithm that is capable to operate actuators in the treatment process (air blowers, sludge pumps, chemical dosage pumps) based in the data measured in the sensors. Figure 5.5 shows the SCADA user interface locate in the operator control room, information of the sensors and the status of the actuators is display for each of the components of the wastewater treatment plant. The human operator is kept constantly informed of the automatic controls being implemented by the remote units and can always assume manual control of the WwTP. Figure 5.6 shows two examples of actuators in this case a manual valve and an automatic valve used to control the air entering the aerated tank. Those devices give flexibility to the WwTP to be operated using the SCADA system but also manually in case it is required.

23

Figure 5.6. Actuators: Manual Valve (left) and Automatic Control Valve (right) In general terms the SCADA system facilitates the labour of the operator and increases the information that he can use to take operational decisions. In the case of the operator interviewed in Gouda WwTP, he mention that he was more confidence with the data that he measure manually in the effluent (Monitoring Type I), to check the performance of the system, instead of the SCADA application. Basically, this exposes the difficulties that automation technologies confront with the human behaviour of fear to unknown or not fully understandable. Although, he has been trained to operate the SCADA system, apparently the level of involvement of the operator has been more at the level of user and this give some disadvantages in terms of the fully use of the system.

At this level the data collected in the monitoring type II is used to control the WwTP, but the flow of data does not stop there. The data measured is also transmitted one level up into a data base and a web based application for managerial purposes in Rijnland Water Board (). There are two different users of that information: engineer advisor of operational process and the managers of the WwTP. The operational advisor is an engineer in charge of help the operators with operational problems, he is the direct user of the web based application, and use it to retrieve information of the trends of the WwTP, statistics and also the current information that is being generated by the on-line sensors. The other users are at the management level, where the information is summarize in statistics and trends that are used to analyse the performance of the system and to generate the yearly report of the WwTP status to the superior levels within Rijnland Water Board and to the Provincial government of Zuid Holland and to the National level at the Ministry of Transport, Public Works and Water Management (through Rijkswaterstaat). The information generated with this type of monitoring for the annual reports is mainly in terms of quantity of water treated, sludge production and consumption of chemicals and energy. The information used for annual reports about water quality parameters and removal efficiencies are based in the monitoring type III.

The Type III monitoring program has as objective the generation of information for performance analysis and control of standards compliance. Thus, the focus of this monitoring program is on the influent and effluent water quality characterisation (53 parameters in total – See Table 10 above), with more emphasis in the effluent as judge by the number of parameters measured. Another characteristic of this monitoring program is that sample is taken automatically using sampling equipment proportional to the flow (Figure 5.7), and the water sample is sent to Laboratory of Rijnland Water Board (Leiden). The sample frequency depends basically on the requirements of the Zuid Hollands Province and specifically on the Rijkswaterstaat, because the Gouda WwTP effluent is discharged to Holandse Ijseel River that is managed by Rijkswaterstaat , contrary to most of the WwTP operated by Rijnland Water Board that discharge to the inland water courses managed by themselves. The major control is on organic mater, nutrients and suspended sediments, then some heavy metals and with less frequency the organic micro pollutants (see details in Table 10 above).

24

Figure 5.7. Automatic Flow Proportional Sampling Device After the sample is analysed and the results are generated the data are quality assessed and included in the data base from where reports can be generated through the web application. The time lag to the data be available in the WwTP is two weeks, which made that information useless for day to day operation of the system, however the information is used for the operational advisor through the web based application when any problem emerge. The data collected is also the key information for all the reports required for compliance and management. Based on that information Rijnland Water Board generates graphs and tables with trends of water quality parameters and use them for planning and management of Gouda WwTP.

Figure 5.8 shows a diagram with the information flow of the Gouda WwTP. The principal flow is between the WwTP in Gouda and the central management in the Water Board in Leiden. There is no communication with the Municipality of Gouda (in charge of the management of the Gouda sewer network) and basic communication through reports with the Rijkswaterstaat (in charge of the management of Hollandse Ijssel River).

Rijnland Water Board

Management Annual Report

Oper Advisor Rep Rep Rep

Lab RWB

Gemeente Gouda ement level Rijkswaterstaat

g DB + WEB Application Zuid Holland Province Mana

SCADA RTC

erational level PLC p O Lab WwTP

Gouda Sewer Network Hollandse Ijssel River Manual Sampling AIR Online Sensors Automatic sampling WwTP

Figure 5.8. Gouda WwTP Information Flow 25

5.2.3 WwTP Data Validation, Filtration, Integration and Storage During the diagnostic of the WwTP monitoring program, little information could be retrieved from the interviews about the data quality assurance, here after; a brief description on these issues is presented. The monitoring program Type I has as limitation that although the operator has been trained to carry out the physic-chemical analysis in the lab, there is not a quality assurance and that is why the validation and filtration of data from monitoring type I is low and the reliability is also low.

The monitoring program Type II is based on sensor that provide data on-line and the RTC algorithm rely on it. That means that the validation and filtration of that information is a critical issue. The most common errors in the on-line data include measurement values out of range, peaks (outliers) and constant (frozen) measurement values (indicating that the sensor is out of order). It is possible to check the data for these typical errors using simple methods known as single data validation (EPA, 2006) and normally those are developed in the interface between the SCADA and the RTC system. Little information could be obtained about that in the case of WwTP of Gouda, however is clear that the system has this validation process because it also generate alarms in case of sensor failures. According to the WwTP operator, the sensors do not fail frequently, which could be a consequence that the instruments used in Gouda (to measure flow on liquid and gas, liquid level, pressure, temperature, oxygen dissolved) are highly developed, simple, reliable and low maintenance (Vanrolleghem and Lee, 2002) basically because they are the most commune instruments used in WwTPs.

The data gather through the monitoring Type III is validated using the procedure of the quality assurance of the Rijnland Water Board Lab that include also a quality certificate for the automatic sampling. In the pass the data that was not valid (do not pass lab standards) was filtrated and not registered in the data base, however, now a days the politic change and those data are included with a note specifying the problem encountered.

The integration of the information from the three monitoring programs, at it has been explained is done in the data base operated in Rijnland Water Board where the data is storage and transformed en information accessible using the web base application. One of the complains of the operational advisor during the interviews was that although the data base and web base application was developed 12 years ago, still is not fully developed, the system is slow and some times the information can not be retrieved.

5.2.4 Analysis of the wastewater treatment plant monitoring system The WwTP was fully re-constructed to a new system in 1999, and the change is not only marked in the process update but also in the way of the system is controlled (operated). It is clear that the designer used the available state of the art in control of wastewater treatment plants. Thus, the system was built with sensors that where fully developed by the time (i.e. oxygen dissolved and suspended sediments), the treatment plant has a complete data transmission system that pass the data measured by the sensor in the process to data loggers and from there to a central computer in the operational room, and from there again the data transmission system help to transmit data between different devices. The WwTP also has a real time control system that is capable to operate actuators in the treatment process. Those actuators were designed with the possibility to operate under variable conditions like variable velocities, flows, water levels or pressures (pumps and blowers), thus giving to the system an operational flexibility and the ability to be controlled using the information collected in the system and the control strategy generated in the controller. This is already an advantage of Gouda WwTP, because it was conceived including SCADA and RTC components, which is not the case in old designed plants that have no available facilities to install sensors and the devices that can implement controller outputs. 26

The monitoring system implemented in Gouda WwTP is simple but reliable and robust and according to the needs and requirements of the local and national water management institutions. However, there is room for improvement at two levels operational and managerial.

The monitoring type I, carried out for the operator lack of quality assurance and is the one that is used for the day to day operation of the system, meaning that it is a key control of the process. Another problem is those data are not used for reporting basically for the lack of quality.

The online monitoring type II is very simple but at the same time robust and require low maintenance which make it more reliable for the real time control purposes. One of the limitations of the existing monitoring and control system is that is based in measurements in only one process (activated sludge) controlling basically oxygen dissolved, and in case of failure operator will not be able to track the problem and identify the process that caused the failure especially in terms of nutrients removal. One option will be include more sensors specialized in nutrients measurements, according with the interviews with operator and managers the WwTP has the capacity to support more sensors but the basic problem is possible economic and the politic of the Rijnland Water Board that only include more complex instrumentations in the biggest WwTPs. However, due to the pressure generated for rising standards and the attention that is gaining the Hollandse Ijssel river it is possible that this system been updated soon.

The monitoring type III has a strong quality assurance that guarantee the quality of the information that is being measured. However, the sampling system is based in automatic composed flow proportional samples, and then the data obtained are average values, which can hide or attenuate picks of pollution discharged to the river. On the other side, the information generated with this monitoring program take within 1 and 2 weeks to get the results back to the wastewater treatment plant, which clearly eliminate any possibility to react on time to any disturbance in the system based on those data.

It is needed definitely more training and involvement of the operators with sensors and SCADA and RTC components and is also needed more training of the users of the web based application in the managerial level and maybe improvements in terms of accessibility to share information from other data bases not only from outside Rijnland Water Board but also with other existing data bases within the institution.

In terms of integration and sharing of information with other components of the urban wastewater system, is clear that there is a basic communication with Rijkswaterstaat that manage the Hollandse Ijssel River. The communication is based in the report of compliance for WwTP effluent standards and the generation of some effluent water quality trends for heavy metals and organic micro pollutants. No information is get it back to Rijnland Water Board from the quality of the River or the impact of the effluent generated in the river due to the effluent discharged. The information sharing and integration with the other side of the system (the sewer network) that is managed by the Municipality of Gouda is almost non existent. Reasons could be that the WwTP does not confront major problems from the sewer network. In terms of hydraulics capacity the system hold by the pump capacity and not even during wet season the capacity had been reached. From the loading point of view the system work with 30% less for what it was designed which give a good assimilation capacity to the WwTP. Thus, from the prospective of the WwTP it might perform successfully even with out major communication with the sewer network, although in the near future with the fully implementation of the water framework directive the integration is needed in order to improve the overall performance of the UWwS.

27

6 Monitoring Network of Hollandse Ijssel River

6.1 Hollandse Ijssel Description

The Hollandse IJssel (Hollandsche Ijssel in Dutch) is a branch of the Rhine delta that flows 46 km westward from through IJsselstein and Gouda to Krimpen aan den IJssel, where it ends in the River which discharge to the North Sea (Figure 6.1). Up to 1285 the Hollandse Ijssel River was a tide river connected to the River at the Nieuwegein. The main concern of the Holland population by that time was to be flooded through that connection, thus it was closed with a dam in 1285. But that brought as a consequence that the flow was reduced and the Hollandse Ijssel River became shallow and navigability was limited. By the time of Napoleon occupation the idea of canalization appears, and in 1862 the complete canalization of the river between Nieuwegein and Gouda was finished joint with a Ship Lock in Gouda. Since then, the first 30 km of the river are known as the Canalized Hollandse Ijssel. The rest of the river still in its natural channel is affected by the tides of North Sea. With time the lock was improved whit new gates and a Sluice with pumps (Waaiersluis and Spuisluis) to control the flow between the canalized side and the natural side of the river (Figure 6.2).

Alphen aan Den Rhine

Utrecht

Gouwe River Waddinxveen Nieuwegein Monfoort Gouda Ship Lock & Sluice Hollandse Ijssel Canalized Isselstein Stolwijkersluis Haastrecht Moordrecht Gouderak

Hollandse Ijssel

Capelle a/d River Ijssel Rotterdam Lek River Storm Surge Krimpen a/d To Barrier Ijssel North Sea Nieuwe Maas River

Figure 6.1. River Hollandse Ijssel

During the flood of 1953, the storm surge from the North Sea sped eastward up the River Nieuwe Maas. When the storm surge met the out flowing Hollandse Ijssel waters, the river water became pent up with no place to go. Along the west side of the Hollandse Ijssel there is a dike named the Groenendijk. The Groenendijk was all that lay between the roiling waters of the storm surge and the Hollandse Ijssel waters, and the densely populated province of . After the flood event the first part of the sea protection constructions was built at the mouth of the Hollandse 28 Ijssel in 1957 (Figure 6.2). Two towers were placed on both sides of the river and a pair of doors measuring 80 meters wide were hung between the towers. These doors are able to be moved up and down vertically, and when there is a risk of flooding, the doors are lowered down into the water. In addition to the surge barrier, a lock was built for those ships that are too high to pass under the doors. This storm surge barrier would only close at high water, so shipping traffic would not be faced with inconveniences throughout the rest of the year and the water from the river can flow to the North Sea.

Figure 6.2. Ship Lock and Sluice at Gouda (left) and Storm Barrier at Krimpen (right) Images retrieved from Rijkswaterstaat and Delta Werk websites

6.1.1 Gouwe River and other Inflows and Outflows The main tributary of Hollandse Ijssel River is the Gouwe River which discharges through out three mouths 37.1 m3/s. Gouwe is a canalized river that flows approximately 14.8 km from Oude Rijn (Old Rhine) in the north to Hollandse Ijssel in the south. The river source is at the Oude Rijn in the municipality, then it cross Boskoop and Waddinxveen and then ended in Gouda where Gouwe branch off in two old flows through the city and a western canal at the main mouth to the Hollandse Ijssel (Figure 6.1 above). Thus the Gouwe has three points of discharge numbered 5(6), 25 and 26 in Figure 6.3. The other ten main tributaries (Q>1m3/s) are also shown in Figure 6.3 and the description is presented in the Table 11.

Eight of the inlets work also as outlets during dry periods and they are used to supply water to the surface water canals in the cities and polders with the purpose to maintain the ground water levels, keep the water quality in good conditions and supply need water with diverse purposes. The outlets are also shown in Figure 6.3 and the characterisation is presented in the Table 12. The main outlet is again the Gouwe canals with an extraction capacity of 32 m3/s composed by the pump capacity of the Pijnacker (5) and a natural inlet/outlet (6).

29

Figure 6.3. Inflows and Outflows of River Hollandse Ijssel. Source: (Janse and Burgdorffer, 2005)

Table 11. Evacuation Capacities to Hollandse Ijssel (Inlet points Cap> 60 m3/min) Water Point No. Area Discharge Point Capacity in Name Managemandt m3/min Waaiersluis and Spuisluis 840 Gouda Rijkswaterstaat 29 Canalized Hollandse IJssel Hollandse Ijssel Gouda 450 Pump Station tpv Waaiersluis Pump Station mr. Pijnacker 5 Boezem Rijnland deel van 100.000 ha Hollandse IJssel at Gouda 2076 Hordijk HHS van Rijnland stadsboezem Gouda polder 25 Hollandse IJssel at Gouda 80 Pump Station Mallegat (Rijnland Water Board) Willemspolder Reeuwijk stadsboezem Gouda polder 26 Hollandse IJssel at Gouda 70 Pump Station Hanepraai Willemspolder Reeuwijk 16 polders Stolwijk and Berkandwou- de Pump Station Verdoold Hollandse IJssel near Gouderak 384 17 4942 ha Stolwijkersluis Hollandse IJssel near 15 Polder de Nesse 545 ha. 40 Pump Station de Nesse Ouderkerk a/d IJssel polders Dand Hoek and Schuwacht Hollandse IJssel near Pump Station Johannes 14 300 2483 ha Krimpand aan dand IJssel Veurink polders Kromme and Geer and Zijde Hollandse IJssel near Pump Station Kromme, Geer 13 80 1140 ha Ouderkerk a/d IJssel and Zijde Pump Station Middel HHS van Schieland and 9 Polder Capelle 609 ha Hollandse IJssel 140 Watering de Krimpanderwaard 11 Pump Station Oostgaarde Polder Esse, Gans- and Blaardorp. 602 Hollandse IJssel near 10 60 Pump Station Hitland ha bebouwde kom Capelle Hollandse IJssel 1,5 km Pump Station Abr. Kroes 8 gem. - polder. 1541 ha 400 bandedandstrooms Moordrecht (bellow)

Hollandse IJssel 1,5 km Pump Station Abr. Kroes 7 Zuidplaspolder and PPA 5701 ha 572 bandedandstrooms Moordrecht (above)

Source: (Janse and Burgdorffer, 2005)

30 Table 12. Extraction Capacities from Hollandse Ijssel (Outlet points Cap> 60 m3/min )

Water Point No. Area Supply from Quality Water- need Name Managemandt requirements (m3/min) Institution Chloride (mg Cl/l) Streefwaarde: 250 Rijkswater-staat 225-360 per 29 Canalized Hollandse Ijssel Hollandse IJssel Waaiersluis at Gouda Utrecht etmaal Maximum requir: 300 Pump Station mr HHS van Rijnland Area Rijnland + Delfland and See Bijl.5 “Verzilting 5 and 6 Hollandse IJssel near Gouda 1920 Pijnacker Hordijk (water board) Schieland HIJ” natuurlijke inlaat Moland bellow 30 Area Krimpanderwaard Canalized Hollandse IJssel 30 Haastrecht 14 Johannes Veurink 13 Kromme Geer and Zijde HHS van Schieland Hollandse IJssel from and de 15 Area Krimpanderwaard Krimpand ann dand Ijssel until 1000 ca. 80 De Nesse Krimpanderwaard 16 Stolwijkse Sluice Verdoold (Water Board) 12 Langeland and Kortland 500-1000 (urban Hollandse IJssel bellow 8 Area Schieland area); remaining 150 Schutsluis SnelleSluis Moordrecht maximum. 200 Source: (Janse and Burgdorffer, 2005)

6.2 Hollandse Ijssel Monitoring System

6.2.1 Description of the monitoring program The analysis of the monitoring system has been focalized in the area of interest for Gouda UWwS, thus the river reach selected has a length of 8.5 km (Figure 6.4). There are three types of monitoring programmes; the first one has as objective the control of inflows and outflows in terms of quantity and quality and is defined in the Water Agreement of 2005 denominated in Dutch “Waterakkoord Hollandsche IJssel en Lek” (Janse and Burgdorffer, 2005). The second one corresponds to the Monitoring Programme of the National Water Systems – (MWTL programme in Dutch) in which only one monitoring station (19) is located in the Hollandse Ijssel river and it is part of the Water Agreement but with more detailed monitoring in terms of parameters and frequencies. The third monitoring programme is carried out by the hydrologic group of Rijnland Water Board and is more focalized in monitoring flows and water levels of the surface waters that reach the Hollandse Ijssel.

The Water Agreement for the Hollandse Ijssel aims to define and fixed the rules of the extraction and discharge of water from the regional systems to the river. The agreement fixed the practice for operation of the system under normal circumstances. It also defines the master operation of the system for complex situations, in which the functioning and protection of housing and water system coincide. The agreement also specifies the control of the system under particular situations as (imminent) salinity, calamities and water nuisance. The signing institutions are: Rijkswaterstaat Zuid Holland on behalf of Rijkswaterstaat of Utrecht and Oost Netherland and the Water Boards of Stichtse Rijnlanden, Schieland en de Krimpenerwaard and Rijnland.

The recording duties and the information flow are defined in Articles 6 and 7 of the Hollandse Ijssel Water Agreement and were based on the existing monitoring programs. With respect to the recording duty of the water administrators, the Article 6 of the Water Agreement defines:

• The water administrators are obliged to measure the quantity of inflows and outflows from or to the Hollandse Ijssel with a day basis frequency (Table 13). • Recording of flows must take place on the basis of measuring or calculations. The water administrators must strive for accuracy in the measuring or calculations, which up to 10% deviate from the really moved water quantity.

31 • The water administrators are in charge also to analyse and register the quality of the water that is discharge to or withdraw from the Hollandse Ijssel River. The parameter and frequencies are presented in Table 13. • After previous agreement with the consultation group of the Hollandse Ijssel Water Agreement (Article 9), each administrator can stipulate how to measure water quality parameters, the frequency and the location of the monitoring points, for its own area. Although the modification of Table 9 is only possible by the unanimous decision of the water management consultation group. • Every year the water administrators must submit a research proposal to the consultation group, which is the base for obtaining data in the coming calendar year for the substance assessment. The research programme must at least include the monitoring of the parameters included in the Table 9 and the additional indicative parameters required.

The Figure 6.4 shows the location of the monitoring points for water quantity and quality to the Hollandse Ijssel and tributaries in the 8.5 km of interest. The Table 13 shows the monitoring program of the Hollandse Ijssel and its main tributaries for the monitoring points show in Figure 6.4.

a. Hollandse Ijssel b. Reach length: 8.5 km

29 30 Inlet / outlet Outlet WwTP Outlet Figure 6.4. Hollandse Ijssel Monitoring Points a. Water Quantity and b. Water Quality. Source: From (Janse and Burgdorffer, 2005)

Table 13. Monitoring Programme of Hollandse Ijssel River – Gouda Influence Zone

Water Management Location Localization X-Y Sampling Place Name Parameters Frequency Storage Report/Use Institution Responsible Number Code Coordinate Water Board De Stichtse Rijnlanden 1 E33 112892 - 446162 Canalized Hollandse Ijssel GHIJ/Haastrecht WQ1 6/year -- Rijkswaterstaat/Annual

Rijkswater-staat Utrecht 29 -- -- Canalized Hollandse Ijssel Waaiersluis and Spuisluis Gouda Flow 365/year -- Rijkswaterstaat/Annual

4 RO114a 105730 - 457460 Gouwe Elke Morgen Nieuwe Zorgen WQ 6/ year Pumping station Pijnacker Flow 365/year 5RO 116107550 - 446000 Hordijk Pump Station Pijnacker Hordijk Gouwe WQ 6/ year Pump Station Pijnacker Hordijk 6 RO116V 107550 - 446000 Gouwe WQ 6/ year Collecting point Data Base Water Board Rijnland Rijkswaterstaat/Annual 24 Gouda 108536 - 446429 Hollandse IJssel WwTP Gouda WQ 6/ year EMIS

Pump Station Mallegat Flow 365/year 25 Malle 108635 - 446680 Pump Station Mallegat Hollandse Ijssel WQ 6/ year Pump Staion Hanepraai Flow 365/year 26 Hane 108910 - 446750 Pump Station Hanepraai Hollandse IJssel WQ 6/ year At the altitud of the juction of 19 GOUDVHVN2 107200 - 445600 Hollandse IJssel Julianasluis/Hollandsche IJssel, WQ / MWTL2 13/year Data Base Rijkswaterstaat/Annual + Rijkswater-staat Zuid-Holland Gouda outer harbour DONAR WFD -- -- 109230 - 446700 Hollandse IJssel Gouda Brug Water Level2 10 minutes Pump Mill bellow 30 -- -- Mill below Haastrecht Flow 365/year Haastrech Stolwijker sluice Flow 365/year Water Board Schieland en de 17 KOP0408 109640 - 446090 Stolwijkersluis -- Rijkswaterstaat/Annual Krimpenerwaard Hollandse IJssel WQ 6/ year Pump Station Verdoold Flow 365/year 16 KOP0427 105980 - 444100 Verdoold Hollandse IJssel WQ 6/ year 1. WQ: water quality parameters. See details Table 14. 2. MWTL: Monitoring Programme of the National Water Systems. See details in Table 15.

32

The water quality parameters measured in the framework of Hollandse Ijssel Water Agreement are presented in Table 14. The required parameters are presented joint with the actual parameters measured by Rijnland Water Board for year 2008. Notice that the parameters had been adjusted to the needs of the administrator.

Table 14. Water Quality Parameters of Hollandse Ijssel Monitoring Water Agreement

Water Quality Parameters to be Measured Water Quality Parameters measured by Rijnland Water Board (2008) First phase: Physico-Chemical Physico-Chemical Total Phosphate Total Fosforous-P and Destoyed Fosfor Total nitrogen Total Nitrogen-N and Destroyed Total Nitrogen Ammonia Ammonium-N and Amoniak-N Salinity Salinity Suspended Sediments Suspended Sediments (Membranfilters and Filter AA) Heavy metal preferably measured on floating substance Heavy Metals Cadmium Zink Mercury Cooper Copper Ncikel Nickel Lead Zinc Chromium Arsenic Parameters in-situ Parameters in-situ Temperature Temperature Oxygen Dissolved Oxygen Porcentage of Oxygen pH Conductivity Steekbemonstering OW Second phase: Depending on a screening study into substances for which have been incorporated in NW4 MTR, and after agreement with the water quality consultation group.

The station Goudavhvn (19 in Figure 6.4 b) is part of the Monitoring Programme of the National Water Systems – (MWTL) and includes much more water quality parameters, 107 in the water and 88 in the suspended sediments. A summary of the group of parameters measured is presented in Table 15. The complete table with the parameters measured are presented in the Appendix .

Table 15. Summary of the Parameters Measured in Station Goudavnvh.

Number of Group of parameters in Suspended sediments Number of Group of parameters in surface water Parameters (centrifugated sample) Parameters Measurings in-situ 14 Measurings in-situ 4 Commonly/Nutrients 14 Commonly/Nutrients 6 Metal 21 Granulometry 6 Polychlorinated bifenyl (PCB) 7 Metal 27 Polycyclic aromatically hydrocarbons (PAK's) 8 Polycyclic aromatically hydrocarbons (PAK's) 16 Organo chlorinated pesticides (OCB) 19 Poly chlorofinated bifenyl (PCB) 7 Fenols and anilin 12 Organo chlorinated pesticides (OCB) 21 Organo Tin Compounds 7 Remaining organic susbstaces 1 Remaining organic substances 2 Total number of parameters 88 Biological parameters 3 Total number of parameters 107

The third monitoring programme is carried out by the Rijnland Water Board, and it is focus on measurement of water levels and flows on the surface water in Gouda and Hollandse Ijssel River. The location of the monitoring points is presented in Figure 6.5 and the measured parameters are presented in Table 16. There are some parameters that are not measured anymore but the information is useful for trends. The data collected is stored in a Data Base denominated HYMOS, since the information used to build the Table 16 was based in the data base available in UNESCO-IHE, the data is only updated until 2005 or 2006.

33 K10

41

45

44 W116 43 47 4246

04 04A Figure 6.5. Monitoring Points of Rijnland Water Board in Gouda Source: HYMOS Data Base

Table 16. Monitoring Programme of

Institution 1 Station Parameter Frequency Period Storage Responsible ID Name ID Name Unit Start End H08 water level at 0800 hour m + NAP 365/year 1/1/1987 1/21/1993 H16 water level at 1600 hour m + NAP 365/year 1/1/1987 1/21/1993 HH1 water level float 1 m + NAP 10 minuten 1/22/1993 7/1/2006 O2 oxygen dissolved mg/l 365/year 1/1/1987 1/13/1994 O2 oxygen dissolved mg/l 10 minuten 1/22/1993 7/1/2006 PH pH value -- 10 minuten 1/22/1993 7/1/2006 CL Salinity mg/l 365/year 1/1/1987 11/29/1996 4 Gouda TW Temperature, water oC 10 minuten 1/22/1993 7/1/2006 AJ Supply annual m3 1/year 1/1/1980 1/1/1995 FJ Evacuation annual m3 1/year 1/1/1980 1/1/1995 BT company situation -- 10 minuten 12/1/1996 6/30/2006 EGV Conductivity mS 10 minuten 12/1/1996 7/1/2006 HH2 water level float 2 m + NAP 10 minuten 12/1/1996 7/1/2006 QQ Flow m3/sec 10 minuten 12/1/1996 7/1/2006 QQ Flow m3/sec 12/year 1/1/1995 12/1/2004 H01 Water level 1st high tide m + NAP 365/year 1/1/1987 11/29/1993 H02 Water level 1st low tide m + NAP 365/year 1/1/1987 11/29/1993 Rijnland Water H03 Water level 1st or 2e high tide m + NAP 365/year 1/1/1987 11/29/1993 Data Base Board H04 Water level 2e low tide m + NAP 365/year 1/1/1987 11/29/1993 HYMOS 04A Gouda HIJ H05 Water level 2e high tide m + NAP 365/year 1/1/1987 11/29/1993 HH1 water level float 1 m + NAP 10 minuten 1/7/1993 5/29/1996 O2 oxygen dissolved mg/l 365/year 1/1/1987 11/29/1996 CL Salinity mg/l 365/year 1/1/1987 11/29/1996 41 kocksluis AJ Supply annual m3 1/year 1/1/1980 1/1/1995 42 mgatgemaal FDK Evacuation artificially, daily m3 365/year 1/1/1987 12/31/2005 FDN Natural Evacuation, daily m3 365/year 1/1/1987 12/31/2005 43 mgatsluis FDK Evacuation artificially, daily m3 365/year 1/1/2003 12/31/2003 44 Hpraai FDK Evacuation artificially, daily m3 365/year 1/1/1987 12/31/2005 45 Havengda ADN Natural Supply, daily m3 365/year 1/1/1987 12/31/2005 46 vduikerwest ADN Natural Supply, daily m3 365/year 1/1/1987 12/31/2005 47 vduikeroost ADN Natural Supply, daily m3 365/year 1/1/1987 12/31/2005 k10 K_Gouda P08 Precipitate cumulative 0800 hour mm/24 uur 365/year 7/1/1957 12/31/2005 CL Salinity mg/l 52/year 1/1/1987 5/21/2006 O2 oxygen dissolved mg/l 52/year 1/1/1987 5/21/2006 W116 W_Gouda TW Temperature, water oC 52/year 6/10/2000 5/21/2006 O2V Oxygen saturation percentage % 52/year 6/24/2000 5/21/2006 NAP: Normal Amsterdam water level. Source: HYMOS Data Base

6.2.2 Data Processing and Information Flow for Hollandse Ijssel River In the area of interest for the UWwS of Gouda, the monitoring of water quantity and quality of the Hollandse Ijssel River and tributaries involve five different institutions, two offices of Rijkswaterstaat: Utrecht and Zuid Holland and three water boards: De Stichtse Rijnlanden, Schieland en de

34 Krimpenerwaard and Rijnland. This make the data processing and information flow more complex, however a basic analysis is presented below base in the information collected.

In general with respect to the information flow the Article 7 of the Water Agreement defines: • By first of July every calendar year, the water administrators must submit a written report to the consultation group of the Water Agreement. The report must include the data for every inflow and outflow and processed for water and substance assessments. Which respect to the way in which the data are supplied, the consultation group is in charge of define the harmonisation of the reports. The reports have to be submitted to the water management consultation group in Rijkswaterstaat Zuid Holland Province. • In extraordinary circumstances (high salinity concentration, water nuisance and water shortage) the administrators of Hollandse Ijssel and tributaries must supply information in daily basis. • For situations in which an intensive contact between different water administrators is needed, Rijkswaterstaat has established a contact list, which is actualized annually and transmitted to all water administrators.

In the three monitoring programs presented for the Hollandse Ijssel, there are basically two types of data collected: water quantity and water quality. In terms of water quantity there was found three different methods to measure the data: in the river mainly water levels are measured using manual stage gages and automatic stage gages, in pumping stations the flows rates are calculated based in measures of secondary parameters (pump capacity, pumping time, storage water levels, etc) or automatic flow meters. In terms of water quality, the majority of the samples are manually collected and analyzed in the lab, part of the parameters are measured in situ using sensors and few of them has on-line monitoring measuring. Depending of the sampling technique, thus the processing of the data is carried out.

Many manual water level gage where found during the field visit, an example is presented in Figure 6.6a. This type of gauge does not produce a continuous record but a single point in time measurement. The water level is directly read from a reference point, in this case is the normal Amsterdam Water Level (NAP in Dutch). Manual water level measurements are converted to instantaneous stream flow using a rating table or flow curve. Rating tables or flow curves for each of these stations are built based on the relationship between a series of periodic water level measurements and their corresponding in-stream flow measurements.

a b

Figure 6.6. Stream Gauges in Hollandse Ijssel River. a. Manual and b. Automatic Stage Gauge. Automatic water level gauges are equipped with a digital level meter. Measurements are made in a vertical stand pipe (stilling well) installed adjacent to the stream (Figure 6.6b). The stream level is the same as the water elevation in the stilling well and a float is used to measure the level. The 35 measurements are done also with respect to NAP and for the maintenance of the correct value each station has a reference level, incorporated in the rural network of water levels. In the case of the water level gauge called Gouda Brug, the monitoring system produces and average value every 10 seconds. This ten seconds average is transmitted into local computer center via radio connection. The data from different locations is added and transmitted to a central computer system in The Hague; after automatic control the ten second average is converted in 10 minutes average and store in the central data based denominated DONAR. The data are stored in a central file that can be consulted by both government services and industry through, among other means, the public telephone network. These data are shown for a number of essential places in the “Actuele Waterdata” website from the National Discharges and Water Level Measuring Program of Rijkswaterstaat (the Department of Public Works and Water Management). The Figure 6.7 shows the current water level in Gouda Brug station for Hollandse Ijssel river (18 to 23 April 2008).

Figure 6.7. Hollandse Ijssel Water Level in Gouda Brug Station Retrived from Actuele WaterData Website (April 2008)

Some of the automatic monitoring stations include water quality parameters. Figure 6.8 shows the example of a gauge that automatically monitors the water level in the Hollandse Ijssel River but also have two more sensors for water quality parameters: conductivity (EGV in dutch) and temperature. The temperature is used to correct the measures. The EGV sensor measure the electric admittance in µS/cm (= microSiemens by centimetre) and is an indirect measure of the quantity of solved substances in water. The surface water quality in the area can vary from 400 µS/cm (very sweetens) to 4,000 µS/cm (very salts). As an example, distilled water has an admittance of 0µS/cm. It means that no solved substances are in it. With EGV sensor all solved salts in surface water are measured and using a co-relation the salinity of the water can be estimated.

Figure 6.8. Water Quality and Water Level Gauge in Hollandse Ijssel River

36 Rijnland water board and the water managers of the water system use the online data as an indicator of the salinity situation in the surface waters and based on that take decision on washing down the water ways with sweeter water. Not only the Hollandse Ijssel River but also the Gouwe canals in Gouda are monitored to keep the salinity at admissible levels using for that the pumping stations available.

6.2.3 The Water Control Practice The water control in above described water management area is generally described in the Water Agreement (Janse and Burgdorffer, 2005) as follows:

• During the period September/October up to April/May, mainly evacuation of water. In the management area as a rule only restricted level variability is admissible and small buffer possibility is present. During a water objection situation, for example obstructed waterways will lead rapidly to too high water levels in the water system and polders, too high groundwater levels and in the extreme case can lead to water nuisance - flooding.

• During the period May up to august mainly supply of water for level maintaining and Flushing. Water need in this period arises among other things by evapotranspiration. In this period level maintaining is necessary to prevent irreversible dryness damage, being uncovered pile foundations and instability of the weirs and dikes. Level maintaining has therefore highest priority. Flushing during a dryness period is carried out for the improvement of water quality in polder areas. In the management areas of Rijnland and the Schieland and the Krimpenerwaard water boards, water is supply to wash down the salinity of water in surface water canals. The limitation in the salinity is needed for avoid nuisance in the crops that are sensitive to salinity. Water supply to the area is also used to limit the infiltration of polluted waters with micro-contaminants, fine sediments and nutrients. The policy of the water administrators is therefore to minimize water pollution and nuisance.

Figure 6.9 shows an example of the control of the flow in the Gouwe Pumping Station, it shows the periods when the pump is used for evacuation of water from the Gouwe canals to the Hollandse Ijssel River and the periods when the canals are supply with water.

2000000

1000000

0

-1000000 Flow (m3/d) Flow

-2000000

-3000000 1/1/93 1/1/94 1/1/95 1/1/96 1/1/97 1/1/98 1/1/99 1/1/00 1/1/01 1/1/02 1/1/03 1/1/04 1/1/05 Time (1993 - 2005)

Figure 6.9. Flow in Gouwe Pumping Station (data from Hymos data base)

37 6.2.4 Analysis of the Hollandse Ijssel Monitoring System The Water Agreement of Hollandse Ijssel River and Tributaries is an important platform for the monitoring network of the system. Monitoring and control of inflows and outflows are clearly defined in the agreement which facilitate the collection of data and the information exchange.

The Hollandse Ijssel River is a very important water way for the Netherlands and play an important role in the evacuation of the surface water to the North Sea, and the supply of water to maintain the delicate balance of water in the surface canals in the city of Gouda. Thus the monitoring of water levels and flows in the river is well developed. In many cases daily data are available and pumping stations and gates are controlled with online monitoring of water levels at the precision of centimetres.

On the contrary, the water quality monitoring network of the Hollandse Ijssel River and tributaries is underdeveloped. Although there exist an important network of monitoring points of water quality, frequencies are low in most of the points (1 or 2 per month). Although the monitoring stations are used to assess the water quality and fulfil the national and international standards, is questionable the ability of the network to quantify the specific impacts generated by the urban wastewater of Gouda, spatially and temporally with a sound level of confidence and precision. With new regulations like the WFD that emphasis the integration of the urban water management and the control of the urban system based in the resulting condition of the receiving system. Thus, in the future it could be needed to implement new sensors to control in real time aditional parameters to the basic ones that are actually used for the control of the system (Temperature, Conductivity, DO).

It is important to highlight that even with the limited information and the complexity of many institutions and user of the water in Gouda, the data collected is greatly used to control the system and there is an important integration of the work of the institutions involved

38

7 Final Considerations

The diagnosis of the monitoring system status included an inventory of the UWwS components and the data network components. Furthermore, the diagnosis helped to answer the following questions: who is in charge of monitoring, what is measured, how is measured, where, when, how the data are transmitted, quality controlled, analysed, used for control purposes, shared with other institutions and stored. Different tools were used to collect the information: structured interviews with staff of the UWwS at operational and managerial levels, visits to the system and the gages for water quantity and quality data collection, transmission and processing and store, review of current operational strategies and analysis of regulatory requirements and guidelines at local and national level.

The UWwS is composed by sewer network that have different schemes: combined, separate, improved separate and pressurized mains. Surface water in the city is also drained through open canals that received in some cases CSOs. A numerous pumping stations help to transport the wastewater downstream in the system till the WwTP where water is treated using an activated sludge process enhanced with nutrients removal. The final discharge of surface canals and the WwTP is the Hollandse Ijssel River, and important national water way that help to connect the North Sea with the Zuid Holland Province. There are 7 institutions that monitor and/or control the components of the UWwS of Gouda: two Rijkswaterstaat offices Utrecht and Zuid Holland (national water administrators), three water boards De Stichtse Rijnlanden, Schieland en de Krimpenerwaard and Rijnland (local water administrators), Gouda Municipality in charge of the sewer system who delegate in Cyclus NV, a private company, the operation of the sewer system. The complexity of the UWwS and the numerous institutions involved create a complex network of monitoring systems, and hamper the integration of data and information collected in each of them. Some of the main findings are presented as follow:

• An integrated analysis of the information collected in each component of the UWwS never was done before and is recognized as one important need for the optimization of the Gouda Urban Wastewater System. • The monitoring system implemented in Gouda UWwS is simple but reliable and robust and according to the needs and requirements of the local and national water management institutions. However, there is room for improvement at two levels operational and managerial. • Each component of the system has its own monitoring program focalized in its own objectives. The sewer is lets monitored although has a monitoring system for operational purposes and a local RTC system for flooding control. The WwTP is the most monitored component in terms of water quantity and quality; also has a local RTC system focused on the control of activated sludge process and sludge production. The Hollandse Ijssel monitoring program is highly distributed within five water administrator institutions and the users of the river. There is an agreement for the monitoring and control of the river which made this system highly controlled. There exists also a regional RTC system focus on flood, drought and salinity control. • Although each component of the UWwS has local RTC systems, there are not integrated strategies for operational purposes. • In terms of integration and sharing of information with other components of the urban wastewater system, there is a basic communication for compliance between the Sewer and WwTP information and the water administrator of Hollandse Ijssel River. The communication is based in the report of compliance for WwTP effluent standards and the generation of some effluent water quality trends for flow and quality discharges. The information sharing between Sewer and WwTP is almost non existent and the operational information is locally acquired with out taking into account impacts in the other components.

39 • The information is spread within the institution involved; even within an institution four different data bases were found. Due to the scattering of the data, the management of the information is more complex. • There are water agreements and inter-institutional communications that open a good opportunity for integrated solution to the problems of the UWwS. Also supported by strengthened legislation in information exchange and integrated urban systems management. • There is a need for better understanding at operational and managerial level of the information flow and the potential of improvement by the better use of existing information and exchange of data collected in the components of the UWwS.

40 8 References

Blois, G. J. d. (2007) Sturingsregels riolering Gouda. (Ed, Royal Haskoning) 1793.9S6950.A0/M08- 01/GJDB/Goes. CEC (1991) Council of the European Communities Directive concerning urban wastewater treatment (91/271/EEC). Official Journal of European Communities, L135, pp. 40 - 52. CEC (2000) Council of the European Communities. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. Official Journal of the European Communities, L327, pp. 1 - 72. Cyclus NV (2008) Cyclus NV. Onze producten en diensten. Riolering., Vol. Access Jan 2008 http://www.cyclusnv.nl/#pagina=1084, Gouda. EC (2003) Guidance Document No 7. Monitoring under the Water Framework Directive. (Ed, Working Group 2.7 - Monitoring) European Communities (EC). EC (2008) Infrastructure for Spatial Information in Europe (INSPIRE). In http://inspire.jrc.ec.europa.eu/index.cfm, Vol. 2008 European Communities (EC). EEA (1996) European Freshwater Monitoring Network Design. (Ed, Nixon, S. C.) European Topic Centre on Inland Waters. European Environment Agency (EEA), Copenhagen, Denmark. EEA (2008) Water Information System for Europe (WISE). In http://water.europa.eu/content/view/15/30/lang,en/, Vol. 2008 European environment Agency (EEA). Copenhagen. EPA (2006) Real Time Control of Urban Drainage Networks. (Ed, EPA’s Office of Research and Development) United State Environment Protection Agency, Washington, pp. 96. Gemeente Gouda (2004) Ontwerp Gemeentelijk Rioleringsplan Gouda 2004 - 2008. In Gouda. Gemeente Gouda (2006) Woonruimten 2006. In Statische Publicatie Gouda, pp. 30. Gemeente Gouda (2007) Bevolking en Grondgebied 2007. In Statische Publicatie Gouda, pp. 56. Gemeente Gouda, Hoogheemraadschap van Rijnland, Hoogheemraadschap van Schieland, Waterschap Wilck&Wiericke and Witteveen+Bos, I. (2003) Waterplan Gouda. (Ed, Afdeling Ruimtelijke Beleid Gemeente Gouda) Gouda. Hoogheemraadschap van Rijnland (2008) Uitwerking Bemonsterings - en Onderzoeksplan. 128 Stedelijk Waterplan Gouda. Leiden. Janse, J. C. and Burgdorffer, M. C. (2005) Waterakkoord Hollandsche IJssel en Lek. (Ed, Rijkswaterstaat Zuid-Holland) Ministerie van Verkeer en Waterstaa, pp. 60. KNMI (2007) Klimatologie. Normalen 1971 - 2000 Station Gegevens. Koninklijk Nederlands Meteorologisch Instituut. www.knmi.nl/klimatologie/. Kristensen, P. and Bøgestrand, J. (1996) Surface Water Quality Monitoring. European Environment Agency, Topic report No 2/1996. National Environmental Research Institute, Copenhagen, Denmark Langeveld, J. (2004) Interactions within Wastewater Systems, Technological University of Delft (TU Delft), Delft. Langeveld, J. and Jong, A. t. (2007) Kansen voor optimalisatie. Royal Haskoning Report, Nijmegen, pp. 32. Lekkerkerk, H.-J., Reitsma, H. T. and Eijer-de Jong, J. E. (2007) Standardization of water management information in the Netherlands. In 3rd International IWA Conference on Automation in Water Quality Monitoring - AutMoNet2007 Gent - Belgium. Lijklema, L. (1995) Water quality standards: Sense and nonsense. Water Science and Technology, Vol 31 pages 321. Lynggaard-Jensen, A. (1999) Trends in monitoring of waste water systems Talanta, Volume 50, 707- 716(710). NZWERF (2002) New Zealand Municipal Wastewater Monitoring Guidelines. (Edited by D.E. Ray). New Zealand Water Environment Research Foundation, Wellington, New Zealand.

41 Rijkswaterstaat (2008) Watermarkt website. (Ed, Ministerie van Verkeer en Waterstaat) http://www.watermarkt.nl. Tamboer, J. (2007) Watersysteembeschrijving en knelpunten stadsboezem Gouda. Technisch rapport. (Ed, Rijnland, H. v.) Hoogheemraadschap van Rijnland, Leiden. Vanrolleghem, P. A. and Lee, D. S. (2002) On-line monitoring equipment for wastewater treatment processes: state of the art. Vol. 47, pp. 1-34. Warmer, H. and Dokkum, R. v. (2002) Water pollution control in the Netherlands. RIZA - Rijksinstituut voor Integraal Zoetwaterbeheer en Afvalwaterbehandeling (Institute for Inland Water Management and Waste Water Treatment), Lelystad, The Netherlands.

42 Appendix 1. List of Water Quality Parameters of Station GOUDVHVN. Water Quality Parameters Measured in Surface Water Item Parameter code Name (Dutch) Name (English) Frequency Veldmetingen 1 KLEUR Kleur Colour 13 2 GEUR Geur Fragrance 13 3 ZICHT Doorzicht Visbility 13 4 E Extinctie Extinctie 13 5 NEERSVM Neerslagvorm Neerslagvorm 13 6 BEWKGD Bewolkingsgraad Bewolkingsgraad 13 7 WINDSHD Windsnelheid wind speed 13 8 WINDRTG Windrichting wind direction 13 9 GOLFHTE Golfhoogte altitude 13 10 TTemperatuur Temperature 13 11 pH Zuurgraad PH value 13 12 O2 zuurstof oxygen 13 13 %O2 Percentage zuurstof Percentage oxygen 13 14 GELDHD Geleidendheid (conductiviteit) conductivity 13 Algemeen/Nutriënten 15 KjNKjeldahl stikstof Kjeldahl nitrogening 13 16 P totaal fosfaat total phosphate 13 17 ZS Zwevende stof (onopgeloste bestanddelen) Floating substance (unsolved components) 13 18 GR Gloeirest Gloeirest 13 19 %GR Percentage gloeirest Percentage gloeirest 13 20 TOC Totaal organisch koolstof Totally organic carbon 13 21 DOC nf Opgelost organisch koolstof Solved organic carbon 13 22 NO2 nf nitriet nitrate 13 23 NO3 nf nitraat nitrate 13 24 NH4 nf ammonium ammonium 13 25 Cl nf chloride hydrochlorate 13 26 SiO2 nf silicaat silicate 13 27 PO4 nf orthofosfaat orthofosfaat 13 28 SO4 nf sulfaat sulfaat 13 Metalen 29 Hg kwik mercury 13 30 Cd cadmium cadmium 13 31 Cr chroom chromium 13 32 Cu koper cooper 13 33 Ni nikkel nickel 13 34 Pb lood lead 13 35 Zn zink zinc 13 36 As arseen arsenic 13 37 Sb antimoon antimony 13 38 Mn mangaan mangenese 13 39 Fe ijzer iron 13 40 B boor boro 13 41 U uranium uranium 13 42 Te telluur tellurium 13 43 Ag zilver zilver 13 44 Ti titaan titanium 13 45 Co kobalt cobalt 13 46 Mo molybdeen molybdenum 13 47 Sn tin tin 13 48 V vanadium vanadium 13 49 Tl thallium thallium 13 Polychloorbifenylen (PCB's) 50 PCB28 2,4,4'-trichloorbifenyl 2,4,4 - trichlorobifenyl 13 51 PCB52 2,2',5,5'-tetrachloorbifenyl 2.2, 5.5 - tetrachlorobifenyl 13 52 PCB101 2,2',4,5,5'-pentachloorbifenyl 2.2, 4,5,5 - pentachlorobifenyl 13 53 PCB118 2,3',4,4',5-pentachloorbifenyl 2.3, 4.4, 5-pentachlorobifenyl 13 54 PCB138 2,2',3,4,4',5'-hexachloorbifenyl 2.2, 3,4,4, 5 - hexachlorobifenyl 13 55 PCB153 2,2',4,4',5,5'-hexachloorbifenyl 2.2, 4.4, 5.5 - hexachlorobifenyl 13 56 PCB180 2,2',3,4,4',5,5'-heptachloorbifenyl 2.2, 3,4,4, 5.5 - heptachlorobifenyl 13

43 Water Quality Parameters Measured in Surface Water Continuation

Item Parameter code Name (Dutch) Name (English) Frequency Polycyclische aromatisch koolwaterstoffen (PAK's) 57 InP indeno(1,2,3-c,d)pyreen indeno (1,2,3-c, d) pyreen 13 58 BghiPe benzo(g,h,i)peryleen benzo (g, h, i) peryleen 13 59 BbF benzo(b)fluorantheen benzo (b) fluorantheen 13 60 BkF benzo(k)fluorantheen benzo (k) fluorantheen 13 61 Flu fluorantheen fluorantheen 13 62 BaP benzo(a)pyreen benzo (a) pyreen 13 63 Ant antraceen antraceen 13 64 Naf naftaleen naphthalene 13 Organochloorbestrijdingsmiddelen (OCB's) 65 cHpClepO cis-heptachloorepoxide cis-heptachloorepoxide 6 66 HpCl heptachloor heptachloro 6 67 aedsfn alfa-endosulfan alpha endosulfan 13 68 bedsfn beta-endosulfan endosulfanendosulfan endosulfan 13 69 aHCH alfa-hexachloorcyclohexaan alpha hexachlorocyclohexaan 13 70 bHCH beta-hexachloorcyclohexaan beta-hexachlorocyclohexaan 13 71 cHCH gamma-hexachloorcyclohexaan (lindaan) range hexachlorocyclohexaan (lindaan) 13 72 dHCH delta-hexachloorcyclohexaan delta hexachlorocyclohexaan 13 73 HCB hexachloorbenzeen hexachlorobenzeen 13 74 aldn aldrin aldrin 13 75 dieldn dieldrin dieldrin 13 76 endn endrin endrin 13 77 idn isodrin isodrin 13 78 24DDT o,p 2,4'-dichloordifenyltrichloorethaan 2.4 - dichlorodifenyltrichloroethaan 13 79 44DDT p,p 4,4'-dichloordifenyltrichloorethaan 4.4 - dichlorodifenyltrichloroethaan 13 80 44DDD p,p 4,4'-dichloordifenyldichloorethaan 4.4 - dichlorodifenyldichloroethaan 13 81 44DDE p,p 4,4'-dichloordifenyldichlooretheen 4.4 - dichlorodifenyldichloroetheen 13 82 PeClBen pentachloorbenzeen pentachlorobenzeen 13 83 HxClbtDen hexachloorbutadieen hexachlorobutadieen 13 Fenolen en anilinen 84 PeClFol pentachloorfenol pentachlorofenol 6 85 s4C9yFol som 4-nonylfenol-isomeren sum 4-nonylfenol-isomeren 6 86 4ttC8yFol 4-tertiair-octylfenol 4-tertiair-octylfenol 6 87 Fol fenol phenol 6 88 ocresl o-cresol o cresol 6 89 oallFol o-allylfenol o allylfenol 6 90 26DC1yFol 2,6-dimethylfenol 2,6-dimethylfenol 6 91 4Cl2C1yFol 4-chloor-2-methylfenol 4-chloro-2-methylfenol 6 92 2Cl6C1yFol 2-chloor-6-methylfenol 2-chloro-6-methylfenol 6 93 26DCl4C1yFol #2432-12-4#2,6-dichloor-4-methylfenol # 2432-12-4 # 2,6-dichloro-4-methylfenol 6 94 bisfnlA bisfenol-A bisfenol a 6 95 An aniline aniline 6 Organotinverbindingen 96 DC4ySn dibutyltin dibutyltin 13 97 TC4ySn tributyltin tributyltin 13 98 T4C4ySn tetrabutyltin tetrabutyltin 13 99 sDFySn som difenyltin-verbindingen sum difenyltin connexions 13 100 MC4ySn monobutyltin monobutyltin 13 101 MFySn Monofenyltin Monofenyltin 13 102 TFySn trifenyltin trifenyltin 13 Groeps en overige organische stoffen 103 VOX Vluchtig organisch gebonden halogeen Briefly organic bound halogeen 13 104 CHOLREM Cholinesteraseremmer Cholinesteraseremmer 13 Biologische parameters 105 AANTPVLME (THTOCOLI) Aantal per volume Number by volume 13 106 CHLFa chlorofyl-a chlorophyll a 13 107 Fytoplankton Kwantitatieve determinatie fytoplankton Quantitative determinatie fytoplankton 13 Opmerkingen nf : na filtratie over 0,45 µm (=opgelost) o,p,m : ortho, para, meta

44 Water Quality Parameters Measured in Suspended Sediments Item Parameter code Name (Dutch) Frequency 1 Veldmetingen 2 DUURBMSRG Duurbemonstering 13 3 Ql Debietoverbemonsteringsperiode 13 4 NGWTTL Natgewichttotaal 13 Algemeen/Nutriënten 5 %DS Percentagedrogestof 13 6 NG Natgewicht 13 7 DG Drooggewicht 13 8 %OC Percentageorganischkoolstof 13 9 KjN Kjeldahlstikstof 10 P totaalfosfaat Korrelgrootteverdeling 11 %KGF2 Percentagekorrelgroottefractietot2um 13 12 %KGF10 Percentagekorrelgroottefractietot10um 13 13 %KGF16 Percentagekorrelgroottefractietot16um 13 14 %KGF20 Percentagekorrelgroottefractietot20um 13 15 %KGF50 Percentagekorrelgroottefractietot50um 13 16 %KGF63 Percentagekorrelgroottefractietot63um 13 Metalen 17 As arseen 18 Hg kwik 13 19 Cd cadmium 13 20 Cr chroom 13 21 Cu koper 13 22 Ni nikkel 13 23 Pb lood 13 24 Zn zink 13 25 Mn mangaan 13 26 Fe ijzer 13 27 Ba barium 13 28 Be beryllium 13 29 Co kobalt 13 30 V vanadium 13 31 Al aluminium 13 32 Ag zilver 13 33 Ti titaan 13 34 Sc scandium 13 35 Sr strontium 13 36 Zr zirkonium 13 37 S sulfide 13 38 Ce cerium 13 39 La Lanthaniden 13 40 Lu lutetium 13 41 Nd neodymium 13 42 Pr praseodymium 13 43 Sm02 samarium 13 Polycyclischearomatischkoolwaterstoffen(PAK's) 44 BbF benzo(b)fluorantheen 13 45 BkF benzo(k)fluorantheen 13 46 Flu fluorantheen 13 47 BaP benzo(a)pyreen 13 48 BghiPe benzo(g,h,i)peryleen 13 49 InP indeno(1,2,3-c,d)pyreen 13 50 Fen fenanthreen 13 51 Ant antraceen 13 52 BaA benzo(a)antraceen 13 53 Chr chryseen 13 54 Pyr pyreen 13 55 DBahAnt dibenzo(a,h)antraceen 13 56 AcNe acenafteen 13 57 Fle fluoreen 13 58 Naf naftaleen 13 59 AcNy acenaftyleen 13 Polychloorbifenylen(PCB's) 60 PCB28 2,4,4'-trichloorbifenyl13 61 PCB52 2,2',5,5'-tetrachloorbifenyl13 62 PCB101 2,2',4,5,5'-pentachloorbifenyl13 63 PCB118 2,3',4,4',5-pentachloorbifenyl13 64 PCB138 2,2',3,4,4',5'-hexachloorbifenyl13 65 PCB153 2,2',4,4',5,5'-hexachloorbifenyl13 66 PCB180 2,2',3,4,4',5,5'-heptachloorbifenyl13 Organochloorbestrijdingsmiddelen(OCB's) 67 HCB hexachloorbenzeen 13 68 aHCH alfa-hexachloorcyclohexaan 13 69 bHCH beta-hexachloorcyclohexaan 13 70 cHCH gamma-hexachloorcyclohexaan(lindaan) 13 71 aldn aldrin 13 72 dieldn dieldrin 13 73 endn endrin 13 74 idn isodrin 13 75 teldn telodrin 13 76 cHpClepOcis-heptachloorepoxide 13 77 tHpClepOtrans-heptachloorepoxide 13 78 aedsfn alfa-endosulfan 13 79 24DDT 2,4'-dichloordifenyltrichloorethaan 13 80 44DDT 4,4'-dichloordifenyltrichloorethaan 13 81 24DDD 2,4'-dichloordifenyldichloorethaan 13 82 44DDD 4,4'-dichloordifenyldichloorethaan 13 83 24DDE 2,4'-dichloordifenyldichlooretheen 13 84 44DDE 4,4'-dichloordifenyldichlooretheen 13 85 HxClbtDen hexachloorbutadieen 13 86 PeClBen pentachloorbenzeen 13 87 HpCl heptachloor 13 Groeps-enoverigeorganischestoffen 88 MINRLOLE Mineraleolie 13 45