W 107 Technical Rule ‑ Standard 02/2016

This Code of Practice W 111 shall apply to pumpingtests during groundwater prospection anddevelopment and to well performancereviews. pumping test or, to be more precise, well oraquifer test is performed between the constructionand casing and the commissioning of a well. Itdocuments the net output of the well that wasachieved during the development stage, and permitsdrawing extensive conclusions about the localhydrogeological and hydraulic conditions. ThisCode of Practice intends to explain how toproperly execute pumping tests to acquire and makeavailable the considerable amount of data in thecorrect form. The information provided by pumpingtests is crucially important for the futureoperation of a well as a repeat pumping test at alater point in time can help identify the well?sageing process and record it appropriately, thusfacilitating the timely initiation of regenerationor rehabilitation measures.

Knowledge of the grain size distribution of water‑conducting granular soil is of great importance for the construction of wells and for the description of the hydrogeological conditions. It is in particular possible to determine the required gravel‑pack diameter in a well's filter section on the basis of the cumulative grain size curve and the grain size distribution curve. In addition, it is possible to derive estimated data for the coefficient of hydraulic conductivity and the porosity of the examined soil sample. Results of the DVGW Research project  Examinations on the stability and clogging of sand and gravel filters during drilling  (DVGW 1982) have been included in the here described procedure to determine the required gravel‑pack diameter. Compared to the Technical Standard W 113  Determination, representation and evaluation of the grain size distribution of water‑conducting granular soils for geohydrological examinations and for the construction of wells  from the year 1983, different practical possibilities for determining the required gravel‑pack diameter and the hydrogeological parameters coefficient of hydraulic conductivity and porosity are demonstrated. Apart from determining the grain size distribution, details on its representation and especially on its evaluation have been provided.

This Code of Practice W 115 provides information on the usual drilling methods and their applications. In addition, it contains references to possible faults during water development work, which may have consequences for operation, maintenance (regeneration, rehabilitation) and dismantling. As a summarising abstract it shall serve anyone involved with drilling operations as starting point for projectrelatedconsiderations.

This Code of Practice W 118 serves as basis for the hydraulic and mechanical dimensioning of wells. The references listed representthe minimum requirements on the dimensioning of vertical filter wells.Well dimensioning shall be performed so that a hydraulically effective, functionally reliable and economic water abstraction from the aquifer is guaranteed in the long run. At the same time, apart from the Basic hydrogeological parameters, the operating company's technical specifications and the well construction technology are of importance. A careful selection from the various options in well dimensioning can often minimise problems during later well operation, for instance ageing phenomena.For the planning specialists in drilling and well construction companies, engineering offices and water utilities, the code of practice shall provide assistance for the hydraulic and static dimensioning of vertical filter wells.

This Technical Standard W 119 serves as basis for the development of wells by desanding. Sand contents arising during well operation can have a disruptive effect. The consequences can for instance be sanding up of the well, destruction of the submersible motor pumps or disruptions in water treatment. In addition, longlastingsand production of a well may lead to soil settlements, which in turn can have a negative Impact on the entire construction.The technical standard defines criteria for assessing the sand content of raw water and provides guide values for a (still to be approved) residual sand content during the development and operation of wells. The requirement of sandfree water (technical absence of sand) raised in DIN 18302 will in particular be explained in more detail.In addition, experts at water utilities, drilling and well construction companies, engineering offices, pertinent authorities and scientific institutions in charge of planning and construction work are provided with aids for the development of wells by desanding.

This Code of Practice W 121 serves as a basis for designing and constructing groundwater monitoring points.The design and construction of groundwater monitoring points is as important for groundwater Monitoring purposes as it is for precautionary, sustainable groundwater protection. Only correctly designed, competently constructed and reliably operating monitoring points can ensure meeting the current requirements of groundwater quality monitoring. A long service life, safe functioning and, in particular, safe sealing,count among some of the important quality features of groundwater monitoring points.This Code of Practice describes how to competently design and construct groundwater monitoring Points for monitoring the quantity and quality of groundwater. It describes the quality requirements for the construction, the building supervision and the acceptance of groundwater monitoring points.

This Code of Practice W 122 comprises all closing‑off structures for groundwater developments by vertical and horizontal filter wells. The new version incorporates operational issues insofar as they have an immediate effect on the requirements placed on the planning and construction of closing‑off structures.

It shall serve as the basis for the construction and casing of vertical filter wells. Given the importance of the safe and hygienic provision of drinking water, the construction and casing of vertical filter is of special significance. Today, important quality parameters of vertical filter wells are, among others, an extended service life, optimum yield, safe functioning (such as safe sealing), ease of regeneration, rehabilitation and well decommissioning.This Code of Practice deals with the state‑of‑the‑art construction and casing of vertical filter wells and the necessary prerequisites. Additionally, it also covers some aspects of well operation with the aim of achieving maximum service life and thus also an economically efficient mode of operation among other objectives. This Code of Practise is intended to give guidance to clients, planners, construction supervisors and contractors, especially during the construction process, but also to operators during the later phase of operation. Last but not least, it aims at facilitating an understanding of the requirements of supervising authorities and at showing the latter the possibilities and constraints inherent in a particular site.

The technical bulletin on hand makes recommendations for these inspections and acceptances of the awarded drilling and well construction work, which have been compiled on the basis of the set of technical rules and which shall be applied on a case‑by‑case basis. It has become apparent that in order to avoid misunderstandings and costly rework, any acceptances and inspections shall have to be agreed beforehand between the parties involved within the scope of the bill of quantities/construction contract, in particular if the specialist company has to make available equipment and facilities at certain dates or work steps. The selection of the acceptances and inspections to be performed in the individual case shall be guided by the hydrogeological conditions and shall be in line with purpose, type and scope of the structure and the materials used.

W 125 Code of Practice 04/2004

W 126 Technical Rule ? Standard 09/2007

W 127 Technical Rule ? Standard 03/2006

This Code of Practice W 128 provides a basis for the drilling and dimensioning of horizontal boreholes and the construction of horizontal filter wells. This Code of Practice does not discuss cut‑and‑cover methods ‑ protected by e.g. pit lining ‑ that are sometimes used in the field.

W 129 Technical Rule ? Standard 04/2012

This Code of Practice W 130 serves as a basis for the regeneration of wells and groundwater monitoring points. Ageing processes frequently compromise water well performance, adversely affecting, in turn, a well?s service life and economic mode of operation. Well operators therefore face the dual challenge of having to identify the most appropriate regeneration methods for each specific case and being able to evaluate the success of the measures taken. Eventually, a direct capacity increase will ensure the economically efficient operation of a well over the long term only when combined with sustainably successful measures. Any well regeneration measures will, therefore, depend on the nature and scope of ageing and on the constructional condition of the well as well as on groundwater protection requirements. This Code of Practice describes the current requirements on the technically safe and hygienically flawless implementation of well regeneration measures, points out the causes of and explains how to identify well ageing processes, among other things, and offers suggestions on how to delay them. It additionally describes the application options and limits of both mechanical and chemical regeneration procedures and/or methods. By applying this Code of Practice, well operators and contractors alike will be able to record and trace the results achieved by the regeneration measures and evaluate their success, from the planning to the implementation and on to the final phase.