GERMAN ATV-DVWK RULES AND STANDARDS

Advisory Leaflet ATV-DVWK-M 145E

Setting-up and Application of Sewer Information Systems

November 2000 ISBN 3-937758-43-7

Publisher Company of ATV-DVWK German Association for Water, Wastewater Theodor-Heuss-Allee 17 D-53773 Hennef Postfach 11 65 D-53758 Hennef Tel. +49 (0)22 42 / 8 72-120 Fax:+49 (0)22 42 / 8 72-100 E-Mail: lumma@atv.de Internet: http://www.gfa-verlag.ded

ATV-DVWK-A 145E

2 November 2000

Preparation

The Advisory Leaflet ATV-DVWK-M 145E presented here was elaborated by the ATV-DVWK Working Group ES-7.1 ”Sewer Database” within the ATV-DVWK Specialist Committee ES-7 “Operation and Support”. The following have collaborated:

Dipl.-Ing. (FH) Hermann Brechtel, Lauf Dr.-Ing. Peter Drewniok, Leipzig Dipl.-Ing. Arnulf Gekeler, Stuttgart (Chairman) Dipl.-Ing. Volkmar Holzhausen, Frankfurt/M. Dipl.-Ing. Dieter Jacobi, Berlin Dipl.-Ing. Heiner Kretzer, Berlin Dipl.-Ing. Jürgen Lüddecke, Hannover Dipl.-Kfm. Hans Müller, Schieder-Schwalenberg Dipl.-Ing. Jürgen Sawatzki, Schwerte Dipl.-Ing. Rainer Schubert, München Dipl.-Ing. Jörg Henning Werker, Köln

All rights, in particular those of translation into other languages, are reserved. No part of this Advisory Leaflet may be reproduced in any form – by photocopy, microfilm or any other process – or transferred into a language usable in machines, in particular data processing machines, without the written approval of the publisher.

© GFA-Gesellschaft zur Förderung der Abwassertechnik e. V., Hennef 2000

Setting and printing of the German original DCM, Meckenheim

Die Deutsche Bibliothek [The German Library] – CIP-Einheitsaufnahme

ATV-DVWK, German Association for Water, Wastewater and Waste: ATV-DVWK Rules and Standards [Medium combination] / ATV-DVWK, Wasserwirtschaft Abwasser, Abfall. – Hennef: GFA, Publishing Company of the ATV-DVWK, Previously under the [German] title of: Abwassertechnische Vereinigung: ATV-Regelwerk Standard M 145E. Setting-up and Application of Sewer Information Systems – 2000 ISBN 3-937758-43-7

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Contents

Preparation 2

User Notes 5

Foreword 5

1 Determination of Terms 5

2 Setting–up of a Sewer Information System 6 2.1 General 6 2.2 Sewer Database 6 2.2.1 Reach and Shaft (Manhole) Files 6 2.2.2 Connection Files 7 2.2.3 Special Structure Files 7 2.3 Geoinformation System 7

3 Contents of a Sewer Information System 7 3.1 Sewer Database 7 3.1.1 Reach Files 7 3.1.2 Shaft (Manhole) Files 8 3.1.3 Connection Files 9 3.1.4 Special Structures Files 9 3.2 Geoinformation System 10

4 Collection, Recording, Maintenance and Supplementing of Data 11 4.1 Collection of Data 11 4.1.1 Principles with the Collection of Data 11 4.1.2 Collection of Basic Data 11 4.1.3 Collection of Factual Data 11 4.2 Recording of Data 11 4.2.1 Principles for the Recording of Data 11 4.2.2 Recording of Basic Data 12 4.2.3 Recording of Factual Data 12 4.3 Maintenance of Data 12 4.3.1 Principles for the Maintenance of Data 12 4.3.2 Maintenance of Basic Data 12 4.3.3 Maintenance of Factual Data 12 4.4 Supplementing of Data 12

5 Processing of Data 12 5.1 General 12 5.2 Requirements on Hardware and Software 13 5.3 Organisation of Data Processing 13 5.4 Data Security 13 5.4.1 Organisational Data Security 14 5.4.2 Technical Data Security 14 5.5 Data Protection 14

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6 Application Possibilities 14 6.1 General 14 6.2 Sewer Maintenance 14 6.3 Sewer Network Calculation 15 6.4 Asset Calculation of a Sewer Network 15 6.5 Graphical Applications and Assessments 15 6.6 Further Applications 15

7 ATV-DVWK Standards 16

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User Notes

This Advisory Leaflet is the result of honorary, technical-scientific/economic collaboration which has been achieved in accordance with the princi-ples applicable therefor (statutes, rules of proce-dure of the ATV-DVWK and the Standard ATV-DVWK-A 400E). For this, according to precedents, there exists an actual presumption that it is textu-ally and technically correct and also generally rec-ognised.

The application of this Advisory Leaflet is open to everyone. However, an obligation for application can arise from legal or administrative regulations, a contract or other legal reason.

This Advisory Leaflet is an important, however, not the sole source of information for correct solutions. With its application no one avoids responsibility for his own action or for the correct application in spe-cific cases; this applies in particular for the correct handling of the margins described in the Advisory Leaflet.

Foreword

In order to identify the possible hazard potential of leaking sewers it was considered necessary to re-cord and document the condition of the sewer sys-tem. In 1987 this was the reason for the tasking of the ATV Working Group 1.7.1 “Sewer Database” in order to show how a status document can be sen-sibly organised.

Automated data processing has established itself everywhere where applications with large amounts of data and necessarily short access times have to be available and, at the same time, a clear data management is demanded. This development has led to consideration being given to the general form and organisation of automatic data process-ing which increasingly should be available immedi-ately at the work place. From this has resulted the concept for sewer information systems which, in their respective forms, have to satisfy the most var-ied demands.

It therefore became necessary to revise and sup-plement the previous Standard ATV-A 145 [not available in English]. Due to the new specifications for the production of the ATV-DVWK Set of Rules and Standards, the Working Group decided to pub-lish the revised version as an Advisory Leaflet.

The essential components for the setting-up and application of a sewer information system are de-scribed in the here presented Advisory Leaflet ATV-DVWK-M 145E.

The Working Group, however, did not see itself to be in a position to give specific details on the cost effects of the information in this Advisory Leaflet. The continuous development in this field of hard-ware and software make it impossible to give reli-able details for a longer period of time.

1 Determination of Terms

The terms used in this Advisory Leaflet are defined as follows:

Defining data assure the clear local allocation of the data of a sewer information system to the parts of the sewer network. Under parts of a sewer net-work come reaches, shafts (manholes), connec-tions and special structures.

Master data describe the location, geometry, func-tion and structural formation of the sewer network.

Basic data: defining data and master data form the basis of a sewer information system. They are therefore designated as basic data.

Status data describe the structural condition of a sewer network at the times of inspection.

Operational data describe the operational status and the maintenance of a sewer network.

Hydraulic data are data which are required for the carrying out of hydraulic calculations and also the result data of hydraulic calculations.

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Cost data are data which are required for the car-rying out of asset assessments and cost determi-nations as well as the results of these calculations.

Factual data: status data, operational data, hy-draulic data and cost data are fact- and purpose-related and are therefore designated as factual data.

File: related data are managed in a file, several files form a database.

2 Setting–up of a Sewer Information System

2.1 General

A sewer information service is an instrument which manages and assesses the information on the sewer inventory, on the sewer operation, on hy-draulic dependencies and on the changes in value as well as other information on a sewer network. The necessary collection, recording and updating for this necessitates high expense and should therefore be placed in relation to the achievable application uses. From these aspects the operator of sewer networks should decide, on the basis of a design concept, whether the prerequisites are pre-sent in his area and his requirements can be met economically and appropriately by the setting up of a sewer information system.

Data management should take place in an efficient sewer database. The integration of the sewer da-tabase in a geoinformation system offers the op-portunity of carrying out graphic and non-graphic assessment on the basis of the same database. Through this a sewer database becomes a sewer information system. Component part of this infor-mation system can sensibly be, for example, also the management of documents, texts and plans.

The setting up of a sewer information system can take place, dependent on the desired application possibilities, in stages.

2.2 Sewer Database

In principle a database should be divided into four groups:

– reach files – shaft (manhole) files – connection files – special structure files.

Each group contains the appropriate basic data for its field and the associated factual data, so that the set-up shown in Fig. 1 results:

Basic data Factual data

Defining data

Master data Status data Opera-

tional data Hydraulic

data Cost data

Reach file

Shaft (manho-le) file

Connection file

Special struc-ture file

Fig. 1: Basic set-up of a sewer database

Indispensable component of each group are the basic data. The allocation of factual data is then dependent on the aspired for versatility of the ap-plication possibilities.

The individual data of each group are differentiated into such which have, of necessity, to be included in order to be able to cover the versatility of the sewer database as well as such data whose sav-ing in individual cases can be useful. With these additional data which, for example, are listed in Section 3, it should, in any case, be examined whether their saving, also with regard to the main-tenance of the data, produces advantages for the use of the sewer database.

2.2.1 Reach and Shaft (Manhole) Files

A stretch of sewer between neighbouring shafts or fictional shafts is defined, within the meaning of this Advisory Leaflet, as “reach”. Shafts are struc-tures in network-specific normal design, which ex-clusively serve for the aeration and ventilation as well as for the monitoring and cleaning of the sewer reaches. Fictional shafts can be introduced for technical data reasons, for example with the ty-ing of a stretch of sewer to a special structure, and

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with amendment of master data or hydraulic data between two shafts.

2.2.2 Connection Files

Within the meaning of this Advisory Leaflet these files include the data of the positioning of all con-nections (branches) in a reach or at a shaft. The files should be so built up that access to the con-nection takes place via the reach and shaft files. So far as connection-related information has to be saved this should be carried out analogously as in a reach and shaft file (e.g. defining terms).

The connection serves for private property drain-age, road drainage or other uses. The various us-ages are defined in the master data (Section 3.1.3 B) as type of usage.

It should be ensured, from a technical database aspect that, in opposition to the types of usage (e.g. drainage of one or possibly more properties), access via the associated connection to the reach file is also possible. Connection to an indirect dis-charger file via the connection file should be capa-ble of being established through suitable inter-faces.

2.2.3 Special Structure Files

Within the meaning of this Advisory Leaflet, com-ponent parts of the sewer system, which are nei-ther reach nor shafts, are designated as special structures. As a rule they have special hydraulic and operational functions. The following, for exam-ple, count as special structures:

• stormwater holding tanks • stormwater overflows • stormwater sedimentation tanks • stormwater tanks with overflow • inlet structures • outlet structures • inverted siphons • pumping stations • special shafts (e.g. gate shafts, backwater

gates)

With the setting up of a special structure file, very particular attention is to be paid as to whether the information requirement can be met by this part of

the sewer database with regard to the number of individual structures and their differentiation.

2.3 Geoinformation System

A geoinformation system is a system for the man-agement and assessment of geographical data. It is useful for a geoinformation system if the digital urban base map (cadastre and topography) is available. For the optimised use of a sewer infor-mation system it is sensible to be able to fall back also on other geographical information, e.g. con-taminated sites, water protective zones, supply and disposal pipelines.

3 Contents of a Sewer Information System

3.1 Sewer Database

3.1.1 Reach Files

A. Defining data

Road number/code Reach number/shaft numbers (from ... to …) If required, additionally: Municipal code Area code Number of the catchment area Number of the wastewater treatment plant Number of the pumping station Number of the special structure Direction of flow

B. Master data

Height of invert at start of the reach Height of invert at end of the reach Year of construction Length of reach Gradient of reach (calculated) Type of sewer (combined wastewater, wastewater, stormwater and similar.) Type of profile Profile height Profile width

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Type of material Functional condition (e.g. out of service) Position coordinates If required, additionally: Type of drainage (gravity, vacuum, pressure drain-age and similar.) Construction method Type of bedding Groundwater condition Type of ownership Pipe length Water protective zone Number of the inventory plan Position in the road space

C. Status data

Date of the inspection Type of inspection Reason for inspection Date of status assessment Status assessment Date of damage repair Type of damage repair Date of status assessment following damage re-pair Assessment after damage repair If required, additionally: Quality factor, hydraulic factor Inspection interval Status description Videotape number Video counter number If required, as subfile: Date of a single damage: Stationing Description of damage If required, additionally: Status assessment Video counter number Photo number

D. Operational data

Maintenance interval Date of last maintenance Type and quantity of deposit Wastewater characteristics Type of treatment If required, additionally: Crew number Particular observations (e.g. water level, odour)

E. Hydraulic data

Sub-catchment area surface Degree of compaction Development densities If required, additionally: Result data

F. Cost data

Data in accordance with Standard ATV-A 133E

3.1.2 Shaft (Manhole) Files

A. Defining data

Shaft number If required, additionally: Municipal code Area code Number of the catchment area Number of the wastewater treatment plant Number of the pumping station

B. Master data

Height of manhole cover Invert height at lowest point Depth of shaft (calculated) Year of construction Shaft length Shaft width Type of shaft Shaft material Position coordinates If required, additionally: Construction method Type of foundation Groundwater conditions Type of ownership Water protective zone Flooding area Position in the traffic space Type of cover Type of sewer (combined wastewater, wastewater, stormwater and similar)

C. Status data

Date of inspection Type of inspection Reason for inspection Date of status assessment Status assessment

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Date of damage repair Type of damage repair Date of status assessment following damage repair Assessment after damage repair If required, additionally: Inspection interval Status description

D. Operational data

Extermination of rats Date and type of bait If required, additionally: Maintenance interval Date of last maintenance

E. Hydraulic data

Observed height of backwater Date of observed backwater If required, additionally: Result data (e.g. frequency of flooding)

F. Cost data

Data in accordance with Standard ATV-A 133E

3.1.3 Connection Files

A. Defining data

Road number/code Reach number/shaft number (from ...to ...) Stationing/number

B. Master data

Type of use (e.g. private property drainage with Parcel No./Building No. – Road drainage – Other use – Not used) Position coordinates If required, additionally: Type of profile Profile height Profile width Height of connection at the reach/shaft (m AMSL) Year of construction/commissioning Type of material Form of connection (e.g. fitting, saddle, connection piece) Ownership structure

Indirect discharger number Type of wastewater Reference to inventory documentation

C. Status data

Data can be saved according to the responsibility for operation and maintenance in accordance with Section 3.1.1 C.

D. Operational data

Data can be saved according to the responsibility for operation and maintenance in accordance with Section 3.1.1 D.

E. Hydraulic data

Data can be saved according to the responsibility for operation and maintenance in accordance with Section 3.1.1 E.

If required, additionally: Permitted amount of discharge

F. Cost data

Data can be saved according to the responsibility for operation and maintenance in accordance with Section 3.1.1 F.

3.1.4 Special Structures Files

A. Defining data

Structure number Shaft numbers (inlets and outlets) If required, additionally: As for shaft file (see 3.1.2 A)

B. Master data

Type of special structure Structure dimensions Year of construction Position coordinates (edge and shaft entrances) Water management characteristic data If required, additionally: Structural, mechanical and electrical engineering description Measurement and control engineering description Manhole cover height Ground water conditions Type of ownership

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Water protective zone Flooding area Position in traffic space Approval data

C. Status data

Date of inspection Type of inspection Reason for inspection Date of status assessment Status assessment Date of damage repair Type of damage repair Date of status assessment following damage re-pair Assessment after damage repair If required, additionally: Description of condition

D. Operational data

Characteristic data of normal operation Characteristic data of special operation Registration of abnormal occurrences If required, additionally: Reference to system documentation Reference to operating instructions Reference to operator’s logbook Maintenance intervals Date of last maintenance

E. Hydraulic data

Hydraulic characteristic data Hydraulic measured data

F. Cost data

Data in accordance with Standard ATV-A 133E

3.2 Geoinformation System

Using a geoinformation system space related data can be recorded, modified, linked, analysed and presented digitally in their graphic and attributive form. Presentation is to be understood as the

preparation of the space-related data for output on a monitor, printer or plotter. A geoinformation sys-tem makes available general and technically spe-cific functions for the processing of graphic data and their attribute data (e. g. thematic colouring according to arbitrary attribute values, intersec-tions). Only in a few cases are all data available in vector form usable in a sewer information system. Therefore a geoinformation system should enable the processing of raster (e. g. urban base map) and vector data.

A geoinformation system should offer the opportu-nity of integrating, as required, discipline-specific functionality for different branches (e. g. sewer, gas, water, general real property cadastre, local development plan). It is then possible to operate several specialist shells or specialist applications within one geoinformation system.

A sewer specialist shell forms the topology of a sewer network corresponding with the object-based data model defined in this Advisory Leaflet. In order to create and update a consistent data in-ventory, discipline-specific correlation conditions, ranges of values and compulsory fields for attribute data as well as functions for testing of plausibility are required. Examples for data inconsistencies, which a specialist shell must prevent, are the link-ing of a sewer reach with a water supply pipeline, the connection of a wastewater sewer to a storm-water sewer or a sewer invert which lies higher than the upper edge of the manhole cover.

A consistent and permanently available data inven-tory is the most expensive part of a sewer informa-tion system. As approximate value one assumes a ratio for hardware:software:data of 1:10:100. In or-der to ensure long-term investment protection it is sensible to keep data in accordance with open and documented standards on appropriate database systems. The geoinformation system, in addition to the already mentioned functions, makes available the functionality of the communication with the da-tabase.

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4 Collection, Recording, Maintenance and Supplementing of Data

4.1 Collection of Data

4.1.1 Principles with the Collection of Data

Due to the great expense collection of data should be carried out once only. For this all necessary data are to be determined and collected as com-pletely as possible. Before data collection it is to be established in what form and with what accuracy the data should be collected. With the collection of the factual data reference is always to be made to basic data already collected, so that a clear as-signment of the factual data to the basic data is obvious.

4.1.2 Collection of Basic Data

The defining data are determined based on the se-lected defining system or, with recording (digitalisa-tion), created automatically. The master data are extracted within the scope of the digitalisation from the sewer inventory plans or from the official map system (atlas), and can be supplemented from ad-ditional documents, for example, construction files, property files, inspection results or other data in-ventories. The data used are to be examined for their correctness on a random sample basis.

If the quality or actuality of the plans for a digitali-sation is insufficient or if errors determined or in-consistencies cannot be corrected or explained, a local monitoring or re-recording by survey is re-quired. The expense of achieving a particular ac-curacy should be measured against the possible usage.

As it is seldom possible to collect data of the same quality for the complete sewer network, the differ-ent sources are to be noted accordingly. In particu-

lar the survey data and digitalised data are to be differentiated from each other through status de-tails. Data fields whose contents are not guaran-teed should also be marked.

New surveys take place fundamentally on a coor-dinate basis. Height details are to be related to MSL.

4.1.3 Collection of Factual Data

Status data are collected as working result of the recording of status. The recording of the status, in particular with shafts and special structures, can take place within the scope of the operationally re-quired inspection. The data recorded should be so constituted that they apply for both the non-man-accessible as well as the man-accessible sewers.

Operational data are collected as a part of mainte-nance. They can also be obtained from working reports.

Hydraulic data are collected for sewer network cal-culations or obtained from these as results. With this the limits of the sub-catchment areas are re-corded graphically in the sewer information sys-tem. The data can be brought up to date with the aid of aerial photography assessment.

The rules of Standard ATV-A 133E apply for the collection of cost data.

4.2 Recording of Data

4.2.1 Principles for the Recording of Data

The recording of the data of the sewer network takes place on two different routes. The master data from the inventory plans are, so far as they are not transferred directly from the surveying into the sewer information system and further proc-essed there, are recorded through digitalisation on the tablet or monitor screen. The recording of fac-tual data is normally carried out on the work station computer by means of menu-driven, formatted in-put masks. Limited values, comparison of data, permitted input formats or symbols must be con-tained in the recording programs. Before the re-

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cording an appropriately high expenditure for the determination of the input controls should be avail-able in order to obtain assured data. Freedom of redundancy should be maintained.

Derived data (e.g. gradients) should be entered for monitoring purposes only. The recorded data should be checked for plausibility.

4.2.2 Recording of Basic Data

With the digitalisation of inventory plans the follow-ing plausibility checks, for example, have proved themselves: limitations for lengths of reach and depths of shaft, indication of reverse gradients and height drops at shafts and special structures in the direction of flow, discharge of wastewater into stormwater sewers and the opposite.

The plausibility checks should be supported by the production of layout plans and longitudinal sec-tions.

4.2.3 Recording of Factual Data

A data comparison with the associated basic data is required for the recording of factual data. Incon-sistencies are to be indicated and clarified.

With the input of factual data, numerical details are fundamentally to be checked using limiting values, other details (material, construction method etc.) should be taken from user-specific truth tables which are produced before recording.

4.3 Maintenance of Data

4.3.1 Principles for the Maintenance of Data

Maintenance of data is understood to be the amendment and updating of existing data as well as repeat recording of status and operational data.

With amendments the previous data is overwritten. With repeat recording and the retention of previous data, additional data is so entered that they can be compared.

The justification for maintenance of data is to be determined organisationally (see Section 5). The updated data are to be checked for plausibility. Changes are to be documented.

4.3.2 Maintenance of Basic Data

The effects of changes of basic data on factual data are to be indicated through appropriate test routines. It is to be ensured that, with changes of basic data, the factual data affected by this are modified or at least correspondingly identified.

4.3.3 Maintenance of Factual Data

With second or repeat recording of status and op-erational data, the recorded data are to be matched with data already recorded in the sewer information system, in order to ascertain inconsis-tencies.

4.4 Supplementing of Data

With the expansion of networks as well as the pro-duction of new shafts or special structures, only data from local survey should be adopted in the sewer information system.

5 Processing of Data

5.1 General

The processing of data in a sewer information sys-tem is dependent on the hardware and software, on the organisation and on the measures for data security and data protection.

Independent of the type and level of upgrading of the computer system employed, the points made below for the processing of data should be in-cluded in the considerations for the employment of the sewer information system. Operators of sewer networks who wish to employ their own data proc-essing systems should process these points ac-cordingly into the design concept.

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5.2 Requirements on Hardware and Software

The high costs for the collection and updating of data as well as organisational changes associated with the introduction of a sewer information sys-tems can be justified only through a long-term and versatile use of the data. Therefore, with the selec-tion of the system, a solution must be sought which offers the corresponding upgrading possibilities. The opportunity should be taken to involve soft-ware suppliers at an early stage.

The following aspects are to be taken into account with the selection of the system:

• Expansion possibilities Connection of additional work station computers as well as additional hardware components

• Hardware Use of the sewer information system via the work station computer without additional hard-ware

• Operating system Hardware-independent operating system

• Database system Selection of an SQL-capable database system independent of hardware and operating system

• Geoinformation system Integration in a hardware-independent geoin-formation system with the possibility of process-ing hybrid graphic data (raster and vector data) using defined interfaces

• Interfaces Efficient interfaces to other geoinformation and graphic systems, to other database systems, to calculation programs, to TV inspection systems and to office communication

• User prompting Simple user prompting matched to the existing graphic surface standard software also for em-ployees without detailed data processing knowl-edge.

5.3 Organisation of Data Processing

The organisation of the data processing must cover all fields of data collection from the introduc-tion of the sewer information system, the training of the users up to and including data security etc. Ac-countability and responsibilities must be deter-mined within the framework of the organisation. In

addition, the documentation of the process of data collection up to and including the user handbook is also part of the organisation.

An important function with this is taken on by the person responsible for the sewer information sys-tem (database manager). System-related and technical tasks are to be differentiated. To the sys-tem-related tasks, depending on the type and ca-pacity of the computer system, belong the creation of a concept for the organisational and technical data security as well as the monitoring of the data security, the assignment of access rights for the users of the sewer information system in accor-dance with the technical responsibilities, the estab-lishment and updating of the user-specific system settings, the allocation and changes of passwords, the instruction of the users in the operation and the introduction of new versions of the user software.

The determination of the responsibilities for data groups or individual data fields corresponds with the technical allocation of tasks. Associated with this is the regulation of the access authorisation. It is recommended that only the posts which are ac-countable for certain data(-groups) are also granted amendment authority for these data while other users may only read these data.

Essentially the documentation must contain the in-structions for data collection and data recording, the description of the hardware and software, in-formation for the database manager and the user handbook for users of the sewer database and the sewer information system.

5.4 Data Security

Under data security is understood here to be the totality of the technical and organisational meas-ures which prevent the saved data from being lost, destroyed or corrupted and an unauthorised ac-cess to the data taking place.

The production of a concept for data security falls with the scope of activity of those accountable for the sewer information system. The measures for data security cover hardware (including communi-cation lines), software, data media and organisa-tion and are to take into account abnormal occur-rences due to natural events (fire, water) and also

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technical failures (power failure, hardware errors, communication line errors), human error (software errors, incorrect operation) and sabotage.

5.4.1 Organisational Data Security

Organisational data security can be provided through the following measures:

Control of access

Unauthorised persons are refused access to the data processing system.

Control of users

The user must verify his user authority with the computer (e.g. through password).

Control of Access

Access authorisation can refer to the reading (tak-ing notice) or amendment (input, correction, dele-tion) of complete data groups or individual data fields and should be assigned according to techni-cal responsibility.

5.4.2 Technical Data Security

The production of a security copy of the complete contents of the sewer information system at certain time intervals for retention at a specially secured or separate location is absolutely recommended.

With a sewer information system with a large num-ber of persons authorised to carry out corrections or deletions, all amendments should be minuted automatically in the database tables (time and type of transaction, old and new contents) and secured on data carriers.

Following an abnormal occurrence the current status of the sewer information system can be re-constructed on the basis of the latest security copy and by assessment of the amendment protocol.

5.5 Data Protection

In the broad sense data protection is understood to be the totality of the legislative, organisational and technical measures which refer to the protection of

the data to be found in a data memory or on data media against unauthorised access. In the narrow sense data protection is understood to be the pro-tection of personal data from misuse (unauthorised use, onward transmission etc.).

As a rule, no personal data is held in the sewer in-formation system. Legal provisions with regard to data protection therefore do not take effect.

For the case of the linking of the sewer information system with other databases or information sys-tems (e.g. residents registration matters) suitable measures are to be taken in order to prevent an improper use.

6 Application Possibilities

6.1 General

The diversity of the application and interrogation possibilities with the evaluation of the data material is dependent on the scope and on the differentia-tion of the input data. The uses of results from ap-plications and interrogations should be weighed against the expense for the determination and maintenance of the data material necessary for this. The results should be able to be presented clearly, intelligibly and not encoded.

6.2 Sewer Maintenance

The relevant facts for inspection, maintenance and structural rehabilitation of sewer system facilities can be documented as status and operational data in the sewer information system.

The inspection program can be set up on the basis of master data. The inspection program can be updated and measures for the improvement of condition determined through the evaluation of status data.

Application programs for sewer and gully cleaning, the employment of a sewer inspection vehicle or of

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monitoring runs for maintenance can, inter alia, be set up and provided with annotations such as dan-ger points, danger of flooding, means for the elimi-nation of rats, heavy deposits or blockages to flow etc., on the basis of the operational data, if re-quired, with the inclusion of status data.

6.3 Sewer Network Calculation

For the monitoring of the efficiency of the existing sewer network the basic data can be linked to the hydraulic data and sewer network calculations can be carried out using suitable computer programs. Determination of costs and financing programs can be developed in combination with the cost data.

6.4 Asset Calculation of a Sewer Network

The precise and complete knowledge of the status of the sewer network is the most important prereq-uisite for the realistic asset assessment of the sewer network. The determination of the system assets takes place using suitable computer pro-grams using the linking of the basic data with the cost data, if required, through the incorporation of the status data.

6.5 Graphical Applications and Assessments

The sewer information system offers the possibility of performing all graphical applications and as-sessments on the basis of the same database as the non-graphical applications. With this a redun-dant data keeping of factual data and plan con-tents with the disadvantages associated with this is avoided.

Using the data of the sewer information systems it is possible to present the sewer network in general plans, longitudinal sections and cross-sections. Through overlaying the sewer inventory with the digital urban base map in vector or raster form, the output of current inventory and general plans to various scales and in various forms is possible. Here it is an advantage for the actuality if the base map is updated in the same geoinformation sys-tem.

An integrated pipeline cadastre can be produced through interfaces to the geoinformation systems of the supply companies. If the supply companies apply the same geoinformation system the data can be simply overlaid.

A further advantage of sewer information system lies in the possibility of linking any arbitrary factual data with the graphical data and thus produce plans for all specialist tasks. Corresponding infor-mation is also useful for public relations.

Status and rehabilitation plans as well as, if re-quired, damage plans can be produced for sewer maintenance; route plans for operations; arithmetic network plans, loading plans and pondage height plans for hydraulic calculation.

Another graphic application within the sewer infor-mation system is the accessing, from the struc-tures or reaches, of data in raster format (digital indications of damage, scanned structural plans etc.) and presenting them on the monitor screen.

6.6 Further Applications

Linking with other databases or information sys-tems as well as further specialist-related applica-tions can be realised through suitable interfaces. Thus, for example, the sewer information system can deliver the basic elements for the determina-tion of variants with sewer planning or for pollutant load calculations.

The linking of the sewer information system with other databases such as those for indirect dis-charger surveillance or the measuring and control engineering monitoring of the sewer network, the pumping stations, and stormwater overflow facili-ties can be planned. The sewer information system can, in addition, also become a component part of an environmental information system.

Through the linking with technical office communi-cations, data from the sewer information system can be adopted in correspondence in letters, ad-ministrative decisions, reports, printed forms, ta-bles and graphical assessments.

ATV-DVWK-A 145E

16 November 2000

7 ATV-DVWK Standards

Standard ATV-A 133E Recording, Assessment and Up-dating of the As-sets of Communal Drainage Facilities