GERMAN ATV RULES AND STANDARDS

W A S T E W A T E R - W A S T E

ADVISORY LEAFLET ATV M 101E

Planning of Drain and Sewer Systems New Construction, Rehabilitaion and Replacement

May 1996 ISBN 3-934984-38-X

Marketing: Gesellschaft zur Förderung der Abwassertechnik e.V. (GFA) Theodor-Heuß-Allee 17 D-53773 Hennef Postfach 11 65

. 53758

Hennef

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ATV Working Group 1.2.1 "Calculation Methods", which elaborated the ATV Standard A 101 in January 1992 has the following members:

Dr.-Ing. H. W. Bröker, Köln BOR Dipl.-Ing. W. Ebeling, Wolfenbüttel Prof. Dr.-Ing. G. Euler, Darmstadt (†) Ltd. RBD a.D. Dipl.-Ing G. Friesecke, Düsseldorf BD Dr.-Ing. L. Gniosdorsch, Frankfurt/Main (†) Ltd. BD Dipl.-Ing U. Keseling, Hagen/Westf. Dipl.-Ing. W. Königer, München BD Dipl.-Ing. A. Kreil, Kassel BD a.D. Dipl.-Ing. E. Malpricht, Stuttgart Dipl.-Ing. G. Milkov, Hamburg Dr.-Ing. R. Pecker, Erkrath (Chairman) Ltd. BD a.D. Dipl.-Ing. R.H. Rieger, Köln Prof. Dr.-Ing F. Sieker, Hannover Dipl.-Ing. K.J. Ueker, Köln

This ATV Advisory Leaflet is based on the ATV Standard A 101, January 1992 and was revised by the following members in an ad hoc working group. The following took part in the 1995 revision:

Dr.-Ing. Holger W. Bröker, Köln StBD Dipl.-Ing. Volker Jansen, Troisdorf Ltd. BD Dipl.-Ing Ulrich Keseling, Hagen/Westf. BD Dipl.-Ing. Albert Kreil, Kassel Dr.-Ing. R. Pecker, Erkrath (Chairman)

Guest: Dipl.-Ing. Rüdiger Heidebrecht, Hennef

The Advisory Leaflet presented here has been prepared within the framework of the ATV committee work, taking into account the ATV Standard A 400 "Principles for the Preparation of Rules and Standards" in the Rules and Standards Wastewater/Waste, in the January. 1994 version. With regard to the application of the Rules and Standards, Para. 1 of Point 5 of A 400 includes the following statement: The Rules and Standards are freely available to everyone. An obligation to apply them can result for reasons of legal regulations, contracts or other legal grounds. Whosoever applies them is responsible for the correct application in specific cases. Through the application of the Rules and Standards no one avoids responsibility for his own actions. However, for the user, prima facie evidence shows that he has taken the necessary care.

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 or translated into a language usable in machines, in particular data processing machines, without the written approval of the publisher.

Gesellschaft zur Förderung der Abwassertechnik e.V. (GFA), Hennef 1996

Produced by: J. F. CARTHAUS GmbH & Co, Bonn

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Contents Foreword 5

1 Scope 5 1.1 Objective 5 1.2 Area of application 6

2. Definitions 6

3. Principles for planning 7 3.1 General 7 3.2 Planning objectives 8 3.3 Requirements on the planner 9 3.4 Given planning data 9

4. Explanatory report 10

5. Water pollution control 10

6. Hydrologic and wastewater engineering initial data 12

7. Hydrologic and hydraulic calculations 12

8. Supplementary investigations 13

9. Quantitative determination 13 9.1 Quantitative determination for the cost assumption 14 9.2 Quantitative determination for the cost appraisal 14 9.3 Quantitative determination for the cost calculation 14 9.4 Quantitative determination for the drawing up of articles and conditions 14 (cost estimate)

10. Determination of costs 14 10.1 General 14 10.2 Cost assumptions 15 10.3 Cost appraisal 15 10.4 Cost calculation 15 10.5 Cost estimate 16

11 Evaluation of planning alternatives 16 11.1 Fundamentals 16 11.2 Economic efficiency investigations 17 11.3 Further evaluation criteria 17

12 Plans 18 12.1 Types and scales of plans 18 12.2 Contents of plans 18

13 Potential for cost savings 19

Bibliography 19

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Appendix 1: Structure and formation of an explanatory report 21 1 Ordering and tasking 21 2 Local conditions 22 3 Fundamental technical principles 23 4 Results of planning 24 5 Constructional organisation, equipment and operation 24 6 Costs 25 7 Time and cost planning 25 8 Summary 25 9 References 25 10 List of annexes and plans 25

Appendix 2: Details and given planning details on lakes and rivers and verification 26

1 Details on lakes and rivers 26 2 Given planning data 26 3 Verification for the fulfilment of the given planning data 27

Appendix 3: Quantitative and qualitative initial data 28 1 Quantitative data 28 2 Data on water and wastewater quality 30

Appendix 4: Given details on precipitation, surface runoff and sewer discharge, results of the hydraulic and hydrologic calculations 31

1 Given details on precipitation 31 2. Run-off 31 3. Sewer discharge 32 4 Results 32

Appendix 5: Breakdown and content of plans 34 1. General plans 34 2 General site plans 34 3 Site plans 34 4 Computer network plans 35 5 Flow diagrams 36 6 General longitudinal sections and longitudinal sections 36 7 Structure and special plans 38

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Foreword There are numerous specialist aspects to be taken into account with the planning of new construction, rehabilitation and renewal measures for drainage systems. If these do not, from the start and to the respectively required degree, flow into the project work, planners, customers and test authorities must reckon with considerably more work than would otherwise be avoidable. Enquiries, subsequent correction or modification of already executed project tasks play an important role in this.

Prime aim of this Advisory Leaflet is to increase the quality of planning. In the interest of its sound applicability, the planning aspects are presented to a considerable extent as headings or in the form of a check-list. The scope of the planning is divided according to different planning phases in order to contain results capable of providing statements for the respectively necessary decisions and actions.

The requirements of the ATV Standard A 101 produced in January 1992 are now covered in DIN prEN 752 " Drainage Systems Outside Buildings". Therefore, this ATV Standard A 101 required adjustment. In accordance with the new rules in the ATV A 400 "Principles for the Preparation of Rules and Standards", January 1994 edition, there is now an issue as Advisory Leaflet.

The Advisory Leaflet attempts, as far as possible without gaps, to present and elucidate the principles and elements of planning of public and larger non-public drainage systems. In this connection particular value is placed on the planning of rehabilitation and renewal measures.

In addition, efforts are made to bring the planning phases into line with the activity phases described in the Remuneration Regulation for Architects and Engineers (HOAI).

Nevertheless it is emphasised that some of the following listed planning services

- do not, in the sense of the HOAI, represent "Basic Services" but rather "Special Services", and

- are not regulated individually in the HOAI such as, for example, studies, general drainage planning.

The application of this Advisory Leaflet is certainly also possible for planning which goes further than the general rules of wastewater engineering, such as, for example, verification of pollution load for overflow structures, investigations of discharge controls. On the other hand, the scope of preparation can, without problem, be limited to the planning of simple or subordinate subjects. The details and statements can then be simplified. Considered in this way this Advisory Leaflet can, even for experienced engineers, be also a valuable aid in their task.

1 Scope 1.1 Objective

The Advisory Leaflet describes recommendations from whose observation functionally efficient and economic drainage systems can be planned.

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These results can be summarised by those responsible for the disposal of wastewater into a technical wastewater action plan (AMP = "Abwasser Maßnahmenplan").

1.2 Area of Application

The Advisory Leaflet applies for the planning of new construction, rehabilitation and renewal measures of drain and sewer systems.

Below are listed, in abbreviated form, the contents and scope of the planning which, in individual cases, derive from the tasking and the desired services for the solution of the tasks under consideration.

The planning tasks are divided, in accordance with the HOAI, into the following activity phases:

- determination of the basic elements (DBE); - initial planning (IP); - draft planning (DP); - approval planning (AP), and - implementation planning (IMP).

The fundamental contents of these activity phases are laid down in the HOAI and are defined precisely in this Advisory Leaflet for the special requirements placed on the planning of drainage systems. With this, the breakdown into activity phases represents a vertical structure by which the respective subsequent activity is built up smoothly from its predecessor.

In addition, there is a horizontal breakdown within the individual activity phases into "basic activities" and "special activities". Basic activities include the activities which are, in general, necessary for the correct fulfilment of a planning task. Special activities are those which, in special cases, are necessary to supplement the basic activities in order to achieve a desired result.

A particular form of planning activity for drainage systems is represented by the Study and the General Drainage Plan. (GDP).

2 Definitions The special forms of planning activity not described in the HOAI are defined below.

Study The study gives first general statements on the realisation of the planning intentions with larger drainage areas. In order to avoid allowing the development of technical drainage problems at this point in the planning, Federal State and local planning objectives, requirements of water management plans, local bylaws, public and private legal contracts and other similar interests should already be taken into account. As a rule, a study includes the determination of basic elements and part of the initial planning.

General Drainage Plan (GDP)

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The general drainage plan, within the overall planning activity, goes considerably further than the "Study". Accordingly, there is a larger number of plans to be prepared which have more sentential force. The GDP includes, as for the study, the problems of larger drainage areas or several community areas and can thus be the basis of further planning activities. The general drainage plan, as a rule, goes further than the initial planning of sewer networks and contains part of the draft planning.

Technical Wastewater Measures Plan (TWMP)

The Technical Wastewater Measures Plan (TWMP) summarises the results of individual planning activities, including costs and timely sequence of the action concepts. It corresponds with legally laiddown wastewater disposal concepts or plans of some of the Federal German States.

3 Principles for Planning 3.1 General

In accordance with the water laws of the Federal German States the basic planning for the production or modification of public sewer networks requires, as a rule, approval within water law. In future, the tasks will mainly consist of rehabilitating or renewing existing sewer networks which are hydraulically overloaded, show too high an overflow frequency or are in a poor structural condition. With this, it can certainly be necessary to involve a considerably larger area in the planning than that of the actual construction measure.

The scope of a planning activity should be agreed well in time by the customer, planner and the responsible specialist authority. This applies in particular to the determination of the basic elements, the initial planning, the study and the general drainage plan as, in connection with this, there are often different concepts on the financial involvement. Taking into account the technical, economic, and ecological necessities - above all with important, cost incurring projects - planning tasks are to be detailed sufficiently so that, through this, the construction and operating costs can be determined accurately.

Bases for the planning of drainage systems are, in addition to the legal regulations (regulation by statutes), for example: - Administrative Regulations, Standards, Advisory Leaflets and similar of the

responsible Federal State and local authorities; - Relevant DIN Standard Specifications - The ATV German Set of Rules and Standards, and - the respective drainage bylaws. The requirements on drainage systems and their planning are contained in DIN EN 752 "Drainage Systems outside Buildings".

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3.2 Planning Objectives

In accordance with § 18b of the Water Resources Law (WHG) wastewater treatment plants are to be erected and operated taking into account the usage conditions and the directions for the discharge of wastewater in accordance with the respective rules of technology which come into question. In this respect, seen today, the following objectives are to be observed with the planning of drainage installations: - harmless collection and conveyance of wastewater, not least for epidemic-hygienic

reasons; - harmless collection and conveyance of stormwater insofar as it cannot be percolated

or irrigated; - reduction of the loading of lakes and rivers; - production of lasting leakproof sewers and the rehabilitation of leaking sewers; - optimisation of production and operating costs; - avoidance of non-acceptable interference with the ecology.

The first two objectives can be achieved with sewers and storage volumes (damping of discharge peaks) or open systems (stormwater) which are sufficiently hydraulically dimensioned. In addition, a wastewater engineering practical layout of sewers, installation of emergency overflows, a control of discharge as well as an appropriate design with the application of suitable materials which satisfy wastewater engineering and hygienic requirements, are of significance.

Moreover, systems for the percolation of non-harmful, untreated precipitation water should be constructed following hydrological examination.

The third objective can be realised, in particular with the following measures:

- reduction of the overflow parameters (overflow frequency, sum of discharges, discharge duration and load) at the structures with overflow in the combined sewer system;

- removal of faulty connections in the separate sewer system (with storm and wastewater sewers);

- reduction of the amount of wastewater (stormwater, combined wastewater and wastewater), e.g. through rainwater percolation, cooling and industrial usage water circulation in commercial and industrial concerns, reduction of water consumption;

- reduction of water inflow from ditches, springs, streams and drainage pipelines (discharge only exceptionally and exclusively into stormwater sewers of the separate system taking into account possible flooding);

- sewer network management.

The fourth objective can be achieved in that a leakproof sewer network is created in the public zone (sewers, shafts) and on private property and leaking sewers are rehabilitated. Through this, on one side, a penetration by ground and percolation water and, on the other hand, an escape of wastewater and its contents into the subsoil and thus into the groundwater are avoided.

The fifth objective can, above all, be realised through greater planning resources, in particular with investigation of different alternative solutions, also with the selection of the

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drainage system, the site of the special structure or by control of discharge. The selection of the drainage system (combined, separate system) can, incidentally, take place according to ATV Standard A 105 "Selection of Drainage Systems". In addition, realistic estimates for the discharges and a sewer network plan matched to the sewage treatment plant are important.

Finally, the sixth objective can be observed if the natural and ecological characteristics such as, for example, the affected fauna and flora, the subsoil and groundwater conditions and their possible changes with the construction and operation of the drainage system can already be taken into account in the planning. With serious conflicts of aims, hydraulic interests take priority with the planning of a sewer system.

3.3 Requirements on the Planner

In order to ensure well-founded planning results and thus the preconditions for a faultless function of the drainage system, planning is to be given only to qualified and appropriately experienced specialists who are familiar with the rules of wastewater engineering. Insofar that, in addition, installations are to be planned in accordance with the status of technology, for example with

- new calculation principles and procedures, - new principles of construction as well as new technology in production, operation and

maintenance of the wastewater system, its facilities or parts thereof,

additional qualifications such as, for example, relevant references, are to be verified.

3.4 Given Planning Data

Before the start of the actual planning tasks, the following data and planning documents, as far as respectively necessary, should, in particular, be available:

- general plans, general site plans and site plans of the planning area, - area usage plan and housing development plans, - inventory plans of the drainage systems, - inventory plans of pipelines of other suppliers, - survey documents and height datum points, - previous drainage plans, - aerial photographs of the drainage area - population and water usage numbers, - direct and indirect dischargers from commercial and industrial concerns, - precipitation data and/or actual rainfall assessments, - water levels and water flows of the surface waters affected, - subsoil data and groundwater levels, - measured dry weather and wet weather run-offs, - details on known bottle-necks and points of constraint within the existing drainage

systems.

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Fundamentally, before the recalculation of an existing sewer network, measurements of the discharges and/or water levels are to be carried out and evaluated for the planning task. Moreover, observed defects or defects substantiated by measurement as well as other operational experiences from the rehabilitation of a sewer network are to be taken into account.

4 Explanatory Report For each planning activity a summarised but exhaustive explanatory report is to be produced. It must correspond with the contents of the respective planning phase. With implementation planning the explanatory report can be dispensed with.

The structure and the organisation of an explanatory report is presented in Appendix 1. The headings listed are an aid to person responsible for compilation, but are by no means exhaustive. On the other hand, not all the aspects listed there have to be covered. Rather it is sufficient, according to the tasking, to process only those which influence the planning. As far as necessary it is to be differentiated between what exists and what is planned. Texts are to be supplemented to the required degree by graphic and tabular presentation.

5 Water Pollution Control Water pollution control covers all measures for the protection of surface waters, of the groundwater and of the soil from adverse influences. It assists the maintenance or the creation of water quality which ensures that the affected lake or river can serve the well-being of the general public and, in harmony with it, usage by the individual.

Legal principles for water pollution control in the Federal Republic of Germany are the introduced supranational agreements (Directives of the Management Board of the European Community such as, for example, the Water Pollution Control Directive of 1976 with its successive directives), the Water Resources Law (WHG), the Wastewater Rates Law (AbwAG), the Federal State Water Laws with the associated statutory regulations and, finally, the decrees, administrative regulations, standards, etc., of the responsible Federal State Water Authorities.

With the planning of drainage systems the question of the wastewater discharge into a lake or river can play an important and decisive role. The discharge of wastewater requires permission under water law in accordance with § 7 of the WHG. It may, however, only then be given for the discharge of wastewater if the observation of certain requirements is ensured (see § 7a, Para. 1 of the WHG).

If no hazardous substances reach the receiving waters with the wastewater then the relevant requirements must be fulfilled according to the recognised rules of technology. On the contrary, should the wastewater contain substances which, due to statutory regulations, are to be assessed as hazardous (see § 7a WHG), then the requirements must correspond with the status of technology. Such requirements result in the implementation of § 7a WHG, from the Wastewater Source Regulation (AbwHerkV) and the "General Outline Administrative Regulation on Minimum Requirements on the Discharge of Wastewater into Lakes and Rivers (Rahmen-AbwasserVwV)" with the respective appendices, which are, in particular, to be observed. The Federal States must

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ensure that the requirements for hazardous substances are already met before discharge into a public wastewater system (sewer network).

For this, the respective Federal State water laws and the so-called Indirect Discharger Regulations are to be observed. In addition, further requirements can be made on a wastewater discharge by the responsible water authority if this appears to be necessary for reasons of water pollution control.

Wastewater systems are to be established and operated taking into consideration the usage conditions and rates for the discharge of wastewater according to the respective rules of technology which come into consideration for this. These rules can include the generally recognised rules of technology as well as the status of technology.

The method of consideration which goes beyond local limitations and the agreement of all users of the lake or river, which are necessary for an effective protection of the surface waters, should be achieved, according to the WHG, through the production of plans for wastewater disposal, of water management general plans and of management plans.

From the aspect of groundwater protection the requirements are to be seen as considerably tighter, as here, according to the given details of the Water Resources Law (WHG), the basis of concern applies. This is to be observed particularly with the selection of construction materials and the construction. With the rehabilitation of local networks the structural condition of the drainage systems are to be determined in addition to the examination of the hydraulic efficiency. So far as systems lie in water catchment areas (water protective areas) additional requirements are to be placed on the wastewater installations see (ATV Standard A 142, DVGW Standard W 101).

The details on the lakes and rivers, the given planning details as well as the required verification necessary, from the water pollution control aspect, are summarised in Appendix 2.

Which planning principles are required in which planning stage is, in individual cases, to be decided according to the special Federal State regulation, the situation of the lake or river, the desired accuracy of planning results and the statement of the problem. It is recommended that, already in the planning stage, one reaches agreement with the responsible water authorities and with the other users of the lake or river. Should nature, landscape conservancy or other ecologically valuable areas be affected by the planning the nature conservancy authorities should be involved at an early stage.

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6 Hydrologic and Wastewater Engineering Initial Data The hydrological and wastewater engineering initial data for the planning of drainage systems listed in Appendix 3 represents a summary of the overall types of data necessary or desirable in the various planning phases. With this, the systems "Drainage Network" (public and non-public sewer systems) and "Lakes and Rivers" are respectively summarised. Which types of data in which planning phase are necessary depend on the required accuracy of the planning results and are to be decided on a case-by-case basis. In accordance with the required accuracy and in accordance with the selected calculation procedure the drainage area is subdivided into sub-catchment areas and calculation stretches.

The types of data, as far as necessary, are to be raised for the actual status and forecast respectively.

7 Hydrologic and Hydraulic Calculations The listings in Appendix 4 represent a summary of the hydrologic and hydraulic calculation steps or procedures which come into question in the various planning phases. Which of these steps or procedures are used in the individual planning phases depends on the significance and complexity of the planning object and on the required information of the planning results.

The scope and the execution capability of the applied calculation procedures, as a rule, increase with the size and wastewater engineering significance of the planning object. Thus one can, for example, continue to apply the time coefficient procedure even with the planning of a small sewer network.

With the rehabilitation calculation of a large city drainage network one would, on the other hand, for example apply a hydraulic-dynamic sewer network model which works, according to the tasking, with different area and network distribution. Further, one would either be able to fall back on existing precipitation details or one would have to base the planning on an own locally executed, valid precipitation analysis. In addition an intensive observation and analysis of the given discharge conditions should take place over an as long as possible period of time.

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8 Supplementary Investigations Further investigations, inter alia, on the subjects below, can be necessary with the planning of a drainage system:

- operational safety of the drainage system • accident prevention measures • operational instructions • maintenance plans • precautions against operational faults • selection of suitable materials

- Determination of the soil permeability (permeability coefficient) - Condition of existing sewer networks (cadastral register)

• age • constructional condition, e.g. fracture sites, leaks, corrosion • deposit condition • faulty connections • commercial and industrial dischargers

- Measurement and control • planning and installation of measurement systems • calibration of measurement sites • production of software for data recording • remote transmission of measured data • development of regulation and control systems

- Data management and evaluation • software production, e.g. for data banks, special evaluations • evaluation of measurements of, for example, precipitation, discharges, water levels, water and wastewater quality as well as damage reports and operational logbooks

- Avoidance or reduction of emissions • noises, e.g., with pump stations drop shafts • gases and odours, e.g. with the outlets of pressure pipelines

- Production of financing and cash-flow plans

- Avoidance or reduction of incursions into nature and the landscape • landscape care companion plan • incursion and balance plan.

9 Quantitative Determination The Quantitative determination is necessary as preparatory task for cost determination (Sect. 10) and the assessment of the planning (Sect. 11). It depends on the requirements to be placed there. With this, the following accuracy is recommended:

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9.1 Quantitative Determination for the Cost Assumption - determination of area size of the drainage area in ha - rough determination of main and connecting interceptor sewers according to length in

m and profile size in mm, - determination of number of special structures such as, for example, stormwater

overflows, stormwater tanks with overflows, stormwater sedimentation tanks, stormwater retention tanks, stream and river intersections including inverted siphon structures and pump stations,

- determination of collection values in total number of inhabitants and population equivalents.

9.2 Quantitative Determination for Cost Appraisal - Quantitative determination on the basis of preplanning or the general drainage plan, - determination of all important sewers according to length in m and profile size in mm, - determination of usable tank volumes in m3 of storage volumes, - determination of reconstructed volumes of structures, divided into above ground and

underground parts in m3, - determination of the delivery flow of pump stations in l/s.

9.3 Quantitative Determination for the Cost Calculations - Quantitative determination with the accuracy which stems from the draft documents.

With this, an accuracy sufficient for the request for tender documentation is still not achieved.

9.4 Quantitative Determination for the Drawing Up of Articles and Conditions (Cost Estimate

- Quantitative determination on the basis of implementation planning in accordance with the Contract Procedure for Construction Services (VOB), Part C and the Contract Procedure for Services (VOL).

10. Determination of Costs 10.1 General

The accuracy of determination of the production costs is to be matched to the selected planning stage and with the section "Quantitative determination". With this the recording of the complete costs for the planned measures are also of particular significance.

Along with the production costs for the drainage installations such as sewers, pump stations, special structures, the following costs, as far as recognisable, are to be taken into account: - construction site, - traffic control/diversion incl. follow-on measures, - re-establishment of roads, - laying of supply lines, - crossing of superior traffic routes, - energy supply for pump stations incl. emergency supply and control,

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- ecological follow-on measures (maintenance of groundwater level, maintenance or re-establishment of green areas, nature protection and marshy areas, balancing and alternative measures),

- ancillary construction measures (e.g. site investigations, planning, construction management, procedures for recording of evidence),

- other follow-on measures, compensation. The costs are either to be calculated into the specific production costs or indicated globally. They can be subdivided into construction sections. With this, if required, administrative agreements and other cost drivers are to be taken into account.

The following classifications are differentiated based on DIN 276, Part 2, "Costs of Buildings, Cost Determinations":

10.2 Cost Assumption

it includes specific costs for

- area drainage in DM/ha - main, collection sewer in DM/m - special structures such as, for example, pump stations, stormwater in

DM/item overflows, stormwater overflow tanks, stormwater retention tanks

- sewage treatment plants in DM/item

10.3 Cost Appraisal

It includes specific costs for

- drains and collection sewers (dependent on profile) in DM/m - usable tank volumes in DM/m3 - reconstructed space (above/under ground part) in DM/m3 - delivery flow from pump stations in DM/(l/s) - connection value of a sewage treatment plant dependent on in

DM/IPE treatment process

10.4 Cost Calculation

It includes costs for main items, e.g. for different types of excavation work in DM/m3, trench support sheeting in DM/m2, raw materials in DM/m..

Equally the costs for ground purchase, release from special rights, ecological follow-on costs, construction overheads (such as, for example, engineer costs, costs for construction site investigations), taxes and unforeseen costs are to be listed specially.

10.5 Cost Estimate

It includes the investment costs by applying locally accepted prices in the articles and conditions and thus represents the detailed allocation of costs. However, here care is to

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be taken that only the production costs for construction and delivery services are recorded.

The accuracy of the cost determinations is greater the more price influencing cost factors are taken into account. These depend, however, on the selected planning stage.

The following types of cost determination are recommended:

Type of cost determination

Study DPR PP DP IP

Cost assumption Cost estimate Cost calculation Offer

x o - -

- x o -

- x - -

_ - x -

- - - o

x = necessary, o = possibly necessary or desirable, - = not necessary

11 Evaluation of Planning Alternatives 11.1 Fundamentals

With the planning of a wastewater engineering measure the consideration of alternative solution possibilities is often unavoidable particularly when the measure concerned requires a considerable expenditure of financial means or, as a result, has significant effects on the environment.

In such cases the alternative solutions are to be selected practically and clearly differentiated against each other.

This can, for example, be the case with the following problems:

- combined, separate or special systems, - collection/transport sewers or retention tanks/sewers with storage capacity and

overflow, - low-lying interceptor sewers or pump stations, - several stormwater overflows or combinations, - connection of distant built-up areas to the actual sewer network or transfer to

neighbouring communities, - retention of the old route or new sewer line, - discharge, usage or percolation of stormwater.

The comparison and calculations for the solution of the above given tasks should be based on comparable principles and cover the effects on the overall system.

The production costs are to be determined with appropriate accuracy (see Sect. 10).

The operating costs (personnel and material costs) should be taken into account, with similar accuracy to the production costs, in the following groups:

- administration,

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- servicing and operation including monitoring, - maintenance, - operating means, - supply and disposal (e.g. energy, water, sludge, screenings).

11.2 Investigations into Operational Efficiency

One obtains, as important result of the investigated planning alternatives, the investment costs to be met and annual operating costs. Economic efficiency investigations are to be carried out in order to obtain the most economic solution. They represent assessment procedures which compare costs of a similar type. For this, the following are suitable:

- the annuity method, and - the discounted cash flow method.

With the annuity method the annual costs (DM/a) are calculated from the capital costs (annual write-off and calculated interest) and the annual operating costs.

With the discounted cash flow method the real value (DM) is determined from the investment costs and the capitalised operating costs. In addition, one differentiates according to statistic methods and dynamic methods, which take into account changing price and cost developments.

The results of the respective economic efficiency investigations are to be set down in a clearly visible form.

11.3 Further Evaluation Criteria

For a comprehensive assessment of planning alternatives, in addition to the economic factors from Sect. 11.2, further monetarily serious or non-ascertainable aspects should be taken into account:

- operating safety, - effects on the environment such as, for example, pollution control, flood and nature

protection, - risks of selected materials, - impairment with implementation of construction, - emissions (also noise and odour), - effects on town development, - timely realisation (urgency, expansion stage, partial success), - financing.

Through these the overall best solution can be found with small cost differences.

For the selection of a planning alternative a benefit-cost analysis can also be useful in special cases.

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12 Plans 12.1 Types and Scales of Plans

For the individual planning stages the following plans come into consideration, which are to be agreed beforehand between those concerned (see also DIN 2425, Part 4):

Type and scale Study GDP IP DP IMP

General plans (Appx. 5, Sect. 1)) Scale = 1:5000 to 1:1000

x

x

x

x

-

General site plans (Appx. 5, Sect. 2) Scale = 1:5000 to 1: 2000

o

x

x

o

-

Site plans (Appx. 5 ,Sect. 3 Scale = 1:2000 to 1:500 or Scale = 1:250

o -

o -

o o

x o

x x

Computer network plans (Appx. 5, Sect. 4) Scale = 1:2500 to 1:500

-

x

o

o

-

Flow diagrams (Appx. 5, Sect. 5) Not to scale

x

x

x

x

-

General longitudinal sections (Appx. 5, Sect 6)Scale = 1:10000/100 to 1:2000/100

o

o

o

o

-

Longitudinal sections (Appx. 5, Sect. 6) Scale 1:1000/100 to 1:500/100 or Scale 1:250/100

o -

o -

o -

x o

x x

Structure and special plans (Appx. 5, Sect. 7) Scale = 1:100 Scale = 1:50 or greater

- -

o -

o o

o o

o x

Time and cost plans (Appx. 5, Sect.7) Construction time plan Cash flow plan

- o

- o

- o

o o

o o

x = necessary, o = possibly necessary or desirable, - = not necessary

12.2 Contents of Plans

The contents of plans depend on the respective objective and the planning phase. The scale of the plan is to be selected accordingly.

Proposals for the structure and the contents of the plans are given in Appendix 5.

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13 Potential for Cost savings With the disposal of wastewater the potential for cost savings is greater in the conceptional, planning area than in the later constructional design and construction. The detailing and assessment of alternatives with different drainage solutions and demands on the ease of drainage is an essential prerequisite for this.

The necessary planning is therefore to be selected directly towards the type and scope of the respective planning tasks. Here the design possibilities and planning flexibility of the technical rules and standards should be fully utilised. To this extent this Advisory Leaflet - applied correctly - can contribute considerably to cost savings with the construction of drainage systems.

Bibliography [Where there is a known translation the title is given in English. For other titles a courtesy translation is given in square brackets.]

[1] ATV: Planung einer Ortsentwässerung, Grundlagen und Hinweise [Planning Local Drainage, Fundamental Data and Notes], ATV-KfK-Arbeitsblatt A 101, 2. Auflage, Februar 1972, GFA, Bonn

[2] ATV: Selection of the Drainage System ATV Standard A 105, January 1996, GFA, Hennef

[3] ATV: Standards for the Hydraulic Dimensioning and Performance Verification of Sewers and Drains, ATV Standard A 110, 1988, GFA, Hennef

[4] ATV: Standards for Dimensioning, Design and Operation of Stormwater Retention Tanks, ATV Standard A 117, June 1977, GFA, Hennef

[5] ATV: Standards for the Hydraulic Calculation of Wastewater, Stormwater and Combined Wastewater Sewers, ATV Standard A 118, June 1977, GFA, Hennef

[6] ATV: Principles for the Computation of Drainage Networks using Electronic Data Processing Systems, ATV Standard A 119, October 1984, GFA, Hennef

[7] ATV: Richtlinien für das Prüfen elektronischer Berechnungen von Kanalnetzen [Standards for the Verification of Electronic Calculations for Sewer Networks], Arbeitsblatt A 120, August 1979, GFA, Hennef

[8] ATV: Niederschlag-Starkregenauswertung nach Wiederkehrzeit und Dauer, Niederschlags-messungen, Auswertung [Precipitation and Heavy rainfall Evaluation According to Repetition Time and Duration, Precipitation Measurements, Evaluation], Arbeitsblatt A 121, Dezember 1985, GFA, Hennef

[9] ATV: Standards for the Dimensioning and Design of Stormwater Structures in Combined Sewers, ATV Standard A 128, 1992, GFA, Hennef

[10] ATV: Construction and Dimensioning of Facilities for the Decentralised Percolation of Non-harmful Polluted Surface Water, ATV Standard A 138, January 1990, GFA, Hennef

[11] ATV: Local Drainage Structures, ATV Standard A 241, March 1994, GFA, Hennef

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[12] ATV: Lehr- und Handbuch der Abwassertechnik 4. überarbeitete Auflage, Band 1, Band 2 [Handbook of Wastewater Engineering, 4th Revised Edition, Vols 1 and 2], Verlag W. Ernst & Sohn, Berlin, München 1995

[13] ATV: Hinweise zur Auswahl unabhängig beratender Ingenieure für Aufgaben im Bereich der Abwasser- und Abfalltechnik, Arbeitsbericht des ATV-Fachausschusses 6.6 "Qualitätsmerkmale bei der Planung und Bauausführung" [Notes on the Selection of Independent Consultant Engineers in the Field of Wastewater and Waste Engineering, Report of the ATV Specialist Committee 6.6 "Quality Characteristics with Planning and Execution of Construction Measures"], Korrespondenz Abwasser 38 (1991), Heft 4, S. 517

[14] ATV: Planning and Construction of Wastewater Pump Stations with Small Inflows, ATV Standard A 134, August 1982, GFA, Hennef

[15] ATV: Hydrologie der Stadtentwässerung, Arbeits-bericht der ATV-Arbeitsgruppe 1.2.6 gemeinsam mit dem DVWK [Hydrology of Municipal Drainage, Report of the ATV Working Group 1.2.6 together with the DVWK], Korrespondenz Abwasser 33 (1986), Heft 2, S. 57 und Korrespondenz Abwasser 34 (1987), Heft 3, S. 263

[16] DVGW: Richtlinien für Wasserschutzgebiete, 1. Teil: Schutzgebiete für Grundwasser [DVGW Standards for Water Protection Zones, Part 1: Protected Areas for Groundwater], W 101, 1995, DVGW, Bonn, 1995

[17] Emschergenossenschaft: Wohin mit dem Regenwasser? Arbeitshilfe für einen ökologisch ausgerichteten Umgang mit Regenwasser in Baugebieten [Where do We Put Stormwater? Aid for an Ecological Handling of Stormwater In Built-up Areas], Eigenverlag, Essen 1993

[18] Geiger, W., Dreiseitl, H.: Neue Wege für das Regenwasser, Handbuch zum Rückhalt und zur Versickerung von Regenwasser in Baugebieten [New Ways with Stormwater, Handbook on the Retention and Percolation of Stormwater in Built-up Areas], Oldenbourg Verlag, München, Wien, 1993

[19] Imhoff, K., Imhoff, K. R.:Taschenbuch der Stadtentwässerung [Handbook of Municipal Drainage], 28. Auflage, Verlag R. Oldenbourg, München, Wien, 1993

[20] Lautrich, R.: Der Abwasserkanal, Handbuch für Planung, Ausführung und Betrieb [The Sewer, Handbook for Planning, Implementation and Operation], 4. Auflage, Verlag Paul Parey, Hamburg, Berlin, 1980

[21] DIN 276, Part 3, Building Costs, Cost Determination

[22] DIN 2425, Teil 4, Planwerke für die Versorgungswirtschaft, die Wasserwirtschaft und für Fernleitungen, Kanal-netzpläne öffentlicher Abwasserleitungen [Planning Instrument for Supply Management, the Economy and for Pipelines, Sewer Network Plans of Public Sewers] Mai 1980

[23] DIN 4045, Wastewater Engineering Vocabulary, December 1985

[24] DIN 19525, Sewerage, Guidelines for Design Development, Febuary 1957

[25] LAWA Leitlinien zur Durchführung von Kostenvergleichsrechnungen [Guidelines on the Execution of Cost Comparison calculations], 1986

[26] DIN prEN 752, Drainage Systems Outside Buildings

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Appendix 1 Structure and Build-up of a Explanatory Report 1 Ordering and Tasking

- Agency for the measure • town, community • association • industry and commercial concern • other

- Reason • new concept of the drainage system • new building area • rehabilitation of defects • further requirements on water pollution control

- Object of planning • significance • aims

- Inclusion in other planning • Federal State planning • project planning • water management plans • other planning

- Requirements of water pollution control • desired water quality • verification of discharges

- Planning agreement • agency for the measure • approval authority • technical specialist authority • others

- Legal questions • drainage bylaws • public statutory agreements • private legal contracts

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2 Local Conditions

- Description of the drainage area • geographical conditions • topographical conditions • area usage

- Connection to other drainage areas • connection pipelines from or to existing or planned areas

- Population conditions • present status • development • tourism

- Commercial and industrial concerns, significant direct or indirect dischargers • existing and/or planned businesses • location, type, size • wastewater relevant production conditions • pre-treatment • stormwater retention tanks

- Precipitation conditions • measurement points • data • evaluation

- Receiving water conditions • designation and course of the receiving water • above-ground watersheds • water flow and water levels • high water, low water, water quality • flooding areas • qualitative and quantitative reception capability • necessary expansion, retention measures

- Underground conditions • site properties • groundwater levels • properties of the groundwater • correspondence between groundwater and receiving waters water levels

- Water supply • protective areas • extracting plants • drinking water barrage • mineral springs

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- Existing wastewater installations • Location • type • condition and efficiency

- Existing wastewater drains into lakes and rivers from • combined sewers • separate sewers • sewage treatment plant • other discharges

- Special problems • nature and landscape conservation • flooding protection • scattered settlements • camping sites • small garden facilities • traffic routes (road, rail, water) • mining subsidence

3 Technical Principles

- Drainage process and system • combined sewer system • separate sewer system • special solution (e.g. rainwater percolation, rainwater usage)

- Given safety details • rainfall frequency • overload frequency • overflow frequency • annual pollution load • water level situation • flooding routes

- Amount and properties of wastewater with wet weather • proportion of paved area • dimensioning rain (rainfall intensity, model rainfall, natural rainfall) • critical rainfall intensity • surface run-off from outside areas • known run-offs, records, measurements

- Amount and properties of wastewater with dry weather • average and peak values of domestic, commercial and industrial wastewater • sewer infiltration water

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- Hydraulic characteristic values for sewers and special structures • operating roughness • coefficient according to Manning-Strickler kSt • loss coefficient • overflow coefficient µ

- Calculation methods • type of procedure or model • principles of the surface and transport model • model parameters (e.g. peak discharge coefficients) • pollution load formulation

4 Results of Planning

- Presentation of individual variants - Evaluation of variants into technical, economic, operational and ecological aspects - Selected solution

• new construction, renewal, rehabilitation • abolition of wastewater installations (sewers, special structures, sewage treatment plants) • line direction determination • locations • effects on the environment

- Technical design • functional description • cross-section and length of sewers • regulation, control • storage volumes • inflows and discharges • pump delivery flow • delivery heights • energy supply • critical combined wastewater discharges.

5 Constructional Organisation, Equipment and Operation

- Sewers • gradient • depth • cross-section shape • material • connection • coating • corrosion protection

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- Regulating and special structures • material • corrosion protection • water and energy supply • disposal • mechanical and electrical equipment (throttles, pumps, transformers, emergency power equipment, flushing devices, scrapers, measurement and remote control facilities)

- Operational aspects • personnel • monitoring • servicing • maintenance • safety facilities (e.g. accident prevention, ventilation and air extraction, fault reporting) • transfer of measured data • disposal of residue

6 Costs

- Production costs - Total costs - Operating costs

- Cost comparisons • annual costs • current values

7 Time and Cost Planning

- Expansion stages - Priorities - Time sequence of construction tranches with production costs - Intermediate and temporary solutions

8 Summary

9 References

10 List of Annexes and Plans

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Appendix 2 Details and Given Planning Details on lakes and Rivers and Verification 1 Details on Lakes and Rivers

1.1 Hydrography

- Designation of the lake or river (receiving waters) - Description of the lake or river (course, expansion condition, retention, usage) - Description of the catchment area (watersheds, morphology, usage, catchment

surfaces) - Changes to the discharge conditions for the forecast

• changes of usage in the catchment area such as, for example, cultivation, afforestation • changes in the lake or river such as, for example, expansion, retention, renaturing.

1.2 Discharges, Water Levels

- Discharge/water level relationship (discharge curve) at the points of introduction - Situation of water levels in the planning area (longitudinal sections) - Average and extreme discharges and water levels - Continuity lines, high and low water statistics - High-water discharge hydrographic curves from the catchment area - Long-term discharge hydrographic curves (discharge continuum or extreme

discharge periods). - Expected changes to the water-level situations and discharges for the forecast.

1.3 Data on Quality of Lakes and Rivers

- Existing water quality class - Measured values (e.g. oxygen content, COD, heavy metals, nutrients) - Preloading and/or existing upstream wastewater discharges - Existing wastewater discharges in the planning area, e.g. from combined sewer

systems, separate sewer systems, sewage treatment plants - Expected changes to the water quality through

• planned additional wastewater discharges • rehabilitation planning.

2 Given Planning Data

2.1 Statutory Regulations and Technical Rules and Standards

- Water Resources Law (WHG) - Wastewater Rates Law (AbwaG) - Federal State water laws - Other Federal or Federal State regulations

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- Drainage bylaws - ATV Rules and Standards - DVGW*) Standards - DVWK**) Rules - DIN Standard Specifications.

2.2 Project-Specific Given Planning Data

- Overall water management plan - Water protection areas - Wastewater disposal plan and/or concept - Management plan - Desired water quality class - Requirements for discharges (minimum, increased requirements) - Relevant parameters of water quality - Ecological constraints - Acceptance capability of the receiving water (qualitative, quantitative) - Given data on overflow frequency and duration, and annual pollution load - Given data on water level situations and discharges - Given data on frequency of the coincidence of overflows from heavy rainfall and

extreme receiving water discharges - Given data on surveillance and self-monitoring the drainage operation.

3 Verification for the Fulfilment of the Given Planning Data

- Evaluations from available drawings - Calculated verification for actual status and forecast with alternative solutions - Verification of necessary measures for expansion or retention of the lake or river - Effects on the environment - Establishment of preconditions for official approval and monitoring - Initiation of a recognised measurement programme - Given data for the drainage operation.

____________________ *) DVGW = German Association of Gas and Water Engineers **) DVWK = German Association of Hydroponic Engineers

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Appendix 3 Quantitative and Qualitative Initial Data 1 Quantitative Data

1.1 Amount of Wastewater Produced with Dry Weather

1.1.1 Domestic wastewater - built-up areas - numbers of inhabitants - amount of wastewater produced per inhabitant and day - settlement densities.

1.1.2 Industrial and Commercial Wastewater

- number, location, type and production conditions of wastewater intensive industrial and commercial concerns

- industrial and commercial areas - local and concern-specific amount of wastewater produced - surge type wastewater amounts produced - wastewater discharge rate - amount of cooling water produced.

1.1.3 Sewer Infiltration Water

- groundwater inflow - land drain water inflow - inflows from above-ground lakes and rivers, wells and springs - discharge rates - faulty connections to wastewater sewers

The different size of the above given components in dry and wet seasons is to be taken into account as necessary.

1.1.4 Total Amount of Wastewater Produced in Dry Weather

For the above given dry weather components the following statistics are to be carried out - individually and superimposed in time - (if necessary by the installation of measurement facilities):

- extreme and individual values (day, week, month, year)

- hydrographic curves (day, week, year)

- trend analysis of previous development

- forecast of future development

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1.2 Amount of Wastewater Produced with Wet Weather

1.2.1 Dimensioning and Decision Parameters

- dimensioning frequencies (annual frequencies for exceeding) or return times • for dimensioning rain • for sewer systems (dam, overdam) • for lakes and rivers in settlement areas • for coincidence of discharge peaks from sewer systems and lakes and rivers • determination of catchment area boundaries such as, for example, outer areas, percolation areas

- reference levels for overdamming frequency of the sewer system - water levels and discharges of the lake or river - flooding and bank boundaries of the lake or river

1.2.2 Precipitation

Locally and regionally valid rain-gauge evaluations for

- rainfall intensity-duration curves - rainfall height curves - rainfall summation curves - point/area rainfall relationships - area precipitation statistics - continuous precipitation series for long-term simulation

1.2.3 Discharge Constitution

The following are to be defined for the sub-catchment areas of the sewer system and of the lake or river:

- degree of compacting - terrain slope (surface gradient) - type of surface, differentiated by permeability and usage - pre-wetting by initial rainfall - rainfall losses (usage, trough, percolation and evaporation losses)

The influence of the season on the discharge constitution is to be taken into account

1.2.4 Discharge Concentration

The following are to be defined for the sub-catchment areas of the sewer system and of the lake or river:

- surface size of the sub-catchment areas - surface roughness - terrain slope - flow length from centre of area to catchment point - characteristic flow times, e.g. longest flow time in the sub-catchment area.

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1.3 Discharge Conveyance The following are to be determined for the calculation sections and special structures of the sewer system and of the lake or river:

- length of the calculation sections - connection of the calculation elements - terrain heights - sole heights - sole gradients - cross-section dimensions and shapes - operational roughness and/or Manning-Strickler coefficient - discharge relevant data of special structures such as, for example, tank volumes,

inflows, discharges

2 Data for Water and Wastewater Quality 2.1 Domestic and Industrial Wastewater

For example BOD5, COD for

- domestic wastewater • area and inhabitant related pollution values • pollution concentrations

- industrial and commercial wastewater • production related pollution values • concentration surges • pollution concentrations

2.2 Stormwater and Combined Wastewater

- Area and inhabitant related pollution values - Size and course of the pollution concentrations - Data on the pollution accumulation on the drainage area and in the sewer network

with dry weather • sum values • over time

- Data on the pollution spoil from the drainage area and from the sewer network with wet weather • sum values • over time

2.3 Sewage Treatment Plant (for existing and planned plants)

- Treatment effect with dry and wet weather • efficiency • concentrations • loads

- Discharge values required by the authorities • discharges • concentrations • loads

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Appendix 4 Given Details on Precipitation, Surface Runoff and Sewer Discharge, Results of the Hydraulic and Hydrologic Calculations 1 Given Details on Precipitation

- Definition of relevant rainfall intensities according to available precipitation statistics - Determination of dimensioning rainfall (block and other model rainfall) from available

precipitation statistics - Evaluation and statistic analysis of local precipitation records - Special investigations

• area precipitation statistics • point and area rainfall relationships • statistically defined rainfall events, e.g. rainfall point diagram • precipitation statistics for dimensioning of stormwater overflows, stormwater tanks and high water pump stations • determination of relevant precipitation events from the discharge statistics

2 Surface Run-off 2.1 Preparatory Work

- Task-specific catchment area division - Determination of the non-pervious and pervious and partially pervious areas in the

sub-areas - Definition of the drainage areas not in the sewer network

2.2 Normal Processes - Definition of peak discharge values, e.g. for time coefficient procedures, time-

discharge factor procedures, sum line procedures

2.3 Precipitation Run-off Models - Run-off build up calculations

• definition of loss quantities (usage, evaporation, trough, percolation losses) • time distribution of loss quantities for non-pervious areas e.g. boundary value method, discharge percentage method • infiltration calculation for pervious and partially pervious areas

- Run-off concentration calculations • application of hydraulic procedures • application of hydrological procedures, e.g. linear individual reservoir, storage cascade, standard unit flow curve hydrodynamic transport model with solution formulation for the movement and continuity equation

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3 Discharge in the Sewer Network

- Selection of the practical calculation method • normal calculation methods such as, for example, time coefficient procedure, time-discharge factor procedure, sum line procedure, flood plan procedure • newer calculation methods hydrological transport model with transfer functions such as, for example, unit flow curve, linear single reservoir, storage cascade

- Accounting for the hydraulic constraints and network properties • receiving water conditions (discharges, water levels) • discharges from other drainage areas • overflows into other drainage areas or receiving waters • special structures with, for example, regulation and control devices, pumps • networking, branching, high points, emergency overflows

4 Results

In addition to input data the following calculation results, each in the respectively necessary scope, are given in the form of lists and, if required, graphically.

4.1 Area

- Total lengths - Total areas - Total number of inhabitants - Average degree of compacting. - Other statistical details such as, for example, sewer volumes, type and number of

special structures

4.2 Sewers

- Discharge capacity - Sewer volumes - Results for different loading conditions such as, for example, dry weather, wet

weather, actual status, forecast • discharges • flow rates • filling heights, water level positions • flow times • degree of utilisation • pressure line gradients • flow conditions (streaming, gushing) • discharge - water level flow curves

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- Special verification such as, for example, • drag stress • water spreading and overdam) frequencies

4.3 Special Structures

- Pump stations • relevant discharges • delivery height (manometric, geodetic) • delivery stream • pump characteristic curves • structure data • usage volumes of the pump sump • operational data of the pressure pipelines • switch-on and switch-off heights • switching frequencies • energy requirement • emergency power supply • overall degree of efficiency • emergency overflow • functional diagram

- Stormwater tanks • type of tank (e.g. stormwater overflow tank, stormwater retention tank, storage sewer, stormwater sedimentation tank) • relevant tank inflows and discharges • dimensioning frequency • associated drainage areas with degree of compacting • calculated flow time in the catchment area • structure data • tank volumes • throttling (regulation, control) of tank discharge • filling, throughflow and emptying times • surface flow rate • inflow and discharge flow curves • water level flow curves • overflow data (overflow discharge sums, overflow frequency, overflow duration) • overflow pollution load, possibly for given time period • emergency overflow • functional diagram

- Stormwater overflows • type of design • relevant inflows and discharges • critical rainfall intensity • calculated flow time in the catchment area • structure data • dimensions of the throttle stretch • overflow data (overflow discharge sums, overflow frequency, overflow duration) • overflow pollution load, possibly for given time period

- Other structures

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For future not yet implemented special structures such as, for example, release structures, inverted siphons, pressure pipelines, pipe bridges, branches, appropriate representation is to be selected in a visible manner.

Appendix 5 Breakdown and Content of Plans 1 General Plans

The general plans should show how the project is to be related to the broader surroundings, to other projects, to other usages and to protective areas. The following inputs are, in accordance with the tasking, recommended for the scales 1:50000, 1:25000 and 1:10000:

- catchment areas (overall, partial, external) - protective areas (water, mineral springs, nature, landscape) - receiving waters with flooding areas - main collector sewers - sewage treatment plants - special structures - contour lines

2 General Site Plans

The general site plans in the scales 1:5000, 1:2500 and 1:2000 should present the project in more detail. Following inputs are recommended:

- catchment areas (overall, partial, external) - protective areas (water, mineral springs, nature, landscape) - water catchment areas - receiving waters with flooding areas - discharge points into the receiving water - areas identified in legally effective area usage and building plans - partial drainage areas - available, planned and disused main collector sewers with details of flow direction, - type, cross-section and gradient of the sewers - special structures with pump stations, stormwater tanks, stormwater overflows,

inverted siphons, outlet structures - sewage treatment plants

3 Site Plans

They should contain all essential measured details, limitations, line directions and structures according to the task. Apart from the arable land boundaries, boundary points, official fixed points and buildings they should include all important topographic details, street names and house numbers. Insofar as inputs which are of significance for the local situation are missing (e.g. street limitation lines, supporting walls), they are to be

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supplemented correspondingly with observation of DIN 18702. 1:2000, 1.1000, 1:500, and, if required, 1:250 are recommended as scales.

According to requirements the site plans can include:

- property boundaries, front garden lines, curbs - property descriptions, plot number, house number, if required more detailed

description of the building - street and building boundary lines, street names - trees - existing and planned sewers with flow direction, cross-section, gradient, sewer

section length, material, if required, lateral inflows, protective pipes - shafts with height of sewer base, manhole cover upper lip height and necessary

height of the terrain - numbering of shaft or sewer and/or sewer section - special structures with, for example, pump stations, lifting stations, diversion

structures, stormwater tanks, stormwater overflows, inverted siphons and pipe bridges, flushing shafts, outlet structures

- operational installations such as, for example, ventilation and air extraction installations, measurement points, control and regulation facilities

- receiving water: name, flow direction, water levels, stationing in kilometres - discharge points into the receiving water or into the drain into the receiving water - natural or predetermined flooding areas - fixed height datum points and, if required, contour lines - catchment areas, surfaced catchment areas and/or discharge coefficient and, if

required, terrain slope, region number - drainage system, free-flow or pressure pipelines - sewage treatment plants

4 Computer Network Plans

The computer network plans should present the essential structure of the sewer network including all special structures. With this, the hydraulic calculations carried out can be checked for their logic and the effects of possible sewer network modifications on the discharge conditions can be viewed better and more quickly.

According to the task and the scope of planning the scales 1:2500, 1:2000, 1:1000, and, if required, 1:500 are recommended.

The computer network plans should contain the follow inputs:

- important street names - all shafts and sewers with flow direction and numbering - receiving water at the discharge points - hydraulic loading of the sewers, differentiated according to the scale of loading and

overloading

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- back-up areas - expansion stages of the sewers to be renewed.

5 Flow Diagrams

The flow diagrams should allow a rapid and comprehensive review of the overall concept of the drainage planning with the inclusion of the receiving water and of the sewage treatment plants.

The flow diagrams are developed from the general plans and general site plans and must be matched with the computer network plans. This schematic presentation should give overall visibility of where and under what conditions the run-off from which areas is discharged into the most important collector sewers and/or receiving waters. This information is, for example, of particular significance with regard to the necessary extra-local method of consideration of the receiving water mentioned in Sect. 3.1.

The flow diagrams should be built up from the elements area, pipe or channel length and structure. They should show, in very simplified but relevantly related form, the following inputs whereby the same, most important designations and numbers as in the above-mentioned fundamental plans are to be used:

- catchment areas (overall, partial, external) - receiving water - main collector sewer, transport stretches - special structures such as pump stations, stormwater tanks, stormwater overflows - control and regulating facilities - sewage treatment plants - discharge points (outlet structures) into the receiving water with stationing in

kilometres

6 General Longitudinal Sections and Longitudinal Sections

All general longitudinal sections and longitudinal sections should be presented with decline from left to right and have the same scale as the site plans.

As a rule the scale 1:100 is to be selected for the height. All height details are to be referred to MSL. It can be practical to show the longitudinal section for the receiving water in another scale to that of the sewers.

The general longitudinal sections with longitudinal scales of 1:10000, 1:5000, 1:2500 and 1: 2000 should allow a good overview of the complete planning measure. Therefore in these plans only the most important inputs appear.

On the other hand, the longitudinal sections with longitudinal scales of 1:1000, 1:500 and, if required, 1:250 allow a comprehensive representation of the planning criteria and results.

The following inputs, according to the respective task, are recommended:

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6.1 Receiving Waters

- River floor heights (in the valley line) - Heights of banks - Existing and planned dikes - Important water levels for processing and hydraulic calculation such as, for example

• mean low water level MLWL (with MLQ) • mean high water level MHWL (with MHQ) • highest known high water level HHWL (with HHQ) with details of annual occurrence • calculated water levels of certain annual occurrences • tidal water levels

- Discharge points from public and private sewers - Junctions and branches of natural and artificial lakes and rivers - Position of cross-sections - Bridges - Sewers, inverted siphons, pipelines, cables - Stationing in kilometres

6.2 Sewers

- Heights of sewer base (water flow), of the manhole cover lip and the terrain - Relevant cellar floor heights - Cross-sections (profiles), clear diameters - Materials, pipe connections - Base gradients and, if required, energy line gradients - Discharge capacities - Backflow lines - Calculated discharge - Shafts and special structures with designations - Measurement points, control and regulation installations - Weir heights - Subsoil according to DIN 18196 - Sewer section lengths - Groundwater level - Inflows and discharges from side sewers (also from future building areas) - Total lengths of partial sections - Transverse pipelines - Street names - Stationing - Special construction measures, e.g. pile foundation, pipe driving - Water level of receiving waters MLWL, MHWL, HHWL at the discharge points (outlet

structures)

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- Pump and lifting stations

7 Structure and Special Plans

The necessary inputs into these plans can be different according to the purpose of the plans and the scope of the planning task.

7.1 Structure Plans

1:100, 1:50 or greater can be chosen as scale. The following inputs are recommended:

- type and quality of materials - dimensions - heights - mechanical and electrical installations - measurement facilities - measurement and reference points - relevant water levels of the receiving water - groundwater levels with details of measurement periods - profiles of subsoil investigations - protective measures

7.2 Special Plans

From the large number of special plans only a few can be named as examples which can be produced in the most varied of scales as diagrams or lists:

- co-ordinating plans (co-ordination with city works, supply agencies, post and similar) - pegging plans - static and constructive plans - register of owners - ecological inventory - recultivation plans - plans on ecological compensating measures - landscape preservation attendant plans - traffic diversion plans - plans for provisions - plans for usage rights, work and buffer strips - cash flow plans - construction time plans