Applied Water Science (v.6, #3)

Transfer of adapted water supply technologies through a demonstration and teaching facility by F. Nestmann; P. Oberle; M. Ikhwan; D. Stoffel; H. J. Blaß; D. Töws; S. Schmidt (215-228).
Water scarcity can be defined as a lack of sufficient water resources or as the limited or even missing access to a safe water supply. Latter can be classified as ‘economic water scarcity’ which among others can commonly be met in tropical and subtropical karst regions of emerging and developing countries. Karst aquifers, mostly consisting of limestone and carbonate rock, show high infiltration rates which leads to a lack of above ground storage possibilities. Thus, the water will drain rapidly into the underground and evolve vast river networks. Considering the lack of appropriate infrastructure and limited human capacities in the affected areas, these underground water resources cannot be exploited adequately. Against this, background innovative and adapted technologies are required to utilize hard-to-access water resources in a sustainable way. In this context, the German–Indonesian joint R&D project “Integrated Water Resources Management (IWRM) Indonesia” dealt with the development of highly adaptable water technologies and management strategies. Under the aegis of the Karlsruhe Institute of Technology (KIT) and funded by the German Ministry of Education and Research (BMBF), these innovative technical concepts were exemplarily implemented to remedy this deficiency in the model region Gunung Sewu, a karst area situated on the southern coast of Java Island, Indonesia. The experiences gained through the interdisciplinary joint R&D activities clearly showed that even in the case of availability of appropriate technologies, a comprising transfer of knowhow and the buildup of capabilities (Capacity Development) is inevitable to sustainably implement and disseminate new methods. In this context, an adapted water supply facility was developed by KIT which hereafter shall serve for demonstration, teaching, and research purposes. The plant’s functionality, its teaching and research concept, as well as the design process, which was accomplished in collaboration with the University Gadjah Mada (UGM), Yogyakarta, Indonesia, is the content of this present paper.
Keywords: Water supply; Adapted technology; Capacity development; Pump as turbine; Wood stave penstock

By means of a case study, the successful implementation of a rheologically optimised cement-based mortar for the construction as well as for the rehabilitation of rain water cisterns is presented in this paper. The material was developed within the scope of a German–Indonesian joint project [“Integrated Water Resources Management” (IWRM)], funded by the German Federal Ministry of Education and Research. Comprehensive rheological investigations are presented which provide the database for the optimization of the mortar with regard to its intended range of application. For the selection of the source materials, special emphasis was placed on the ready availability at low cost. The rheological properties of the fresh mortar allow an easy workability by hand while the hardened mortar shows a durable and tight appearance at the same time. The developed material can be used as a coating for walls, floors and ceilings of cisterns, for the local rehabilitation of damaged areas only or even as a construction material for complete new cisterns. The future multiplication of the IWRM project results within the region was assured by a local capacity development when the presented material concept was applied in practise in Indonesia for the construction of sustainable rain water cisterns in Gunung Kidul.
Keywords: Cement; Concrete; Concrete technology; Rheology; Additives; Cisterns; Rehabilitation

Bypassing and tightening of an underground water retention system in permeable karst: case study of the hydropower plant (HPP) Bribin, Indonesia by Peter Kudella; Iryna Loges; Thomas Mutschler; Elisabeth Eiche; Julia Ruppert; Thomas Neumann (241-257).
In the framework of the Integrated Water Resources Management (IWRM) joint research project in the karst area of Gunung Kidul, Province of Yogyakarta Special Region on the Java Island, Indonesia, an underground hydropower driven water extraction facility in the cave “Bribin” was developed using pump-as-turbine-driven systems for freshwater supply of the rural area. As numerous other caves in the Gunung Kidul area, Bribin is part of a ramified system of all-season water-bearing subterraneous rivers and natural caves in karstic limestone. The elliptic cross section of the cave was completely closed with a concrete barrage, thus creating a year-round underground retention volume with an operational storage level of approx. 15 m. This contribution highlights the geotechnical and geohydraulic challenges handled within the sub-project “Short-time and long-time behaviour of karst rock surrounding pressure-bearing underground water-retaining structures”. One key to the feasibility of an artificial water retention scheme in a natural cave is to ensure the mechanical stability of the cave roof and sidewalls. The necessary geotechnical investigations are described. Another key to the effectiveness of such a water retention concept is the control and minimization of “lost” seepage water bypassing the barrage structure through the karst rock mass. Measures to monitor and to explain the seepage phenomena are presented as well as grouting efforts to minimize them. The limitations of improving the overall tightness will be discussed. Interpretation includes the use of analytical and numerical methods.
Keywords: Seepage; Monitoring; Borehole camera; Grouting; Numeric Modelling; Permeability

Populated karst landscapes can be found all over the world, although their natural boundary conditions mostly lead to distinct challenges regarding a sustainable water supply. Especially in developing and emerging countries, this situation aggravates since appropriate technologies and water management concepts are rarely available. Against this background, the interdisciplinary, German-Indonesian joint project “Integrated Water Resources Management (IWRM) Indonesia”, funded by the German Federal Ministry of Education and Research (BMBF), focused on the development and exemplary implementation of adapted techniques to remedy the partly severe water scarcity in the region Gunung Sewu. This karst area, widely known as “Java’s poorhouse”, is located on the southern coast of Java Island and distinctly suffers from the mentioned constraints. Under the aegis of the Karlsruhe Institute of Technology (KIT), the conceptual and technical achievements of the “IWRM Indonesia” joint research project are characterized by a high potential for multiplication not only for karst areas but also for non-karst regions. One of the project’s major accomplishments is the erection of an innovative hydropower-driven water supply facility located in a karst cave 100 m below ground and continuously supplying tens of thousands of people with fresh water. Referring to the plant’s innovative character and the demanding conditions on-site, the implementation was a highly iterative process leading to today’s autonomous operation by an Indonesian public authority. Based on the experiences gained during design, construction, operation and monitoring phase, this paper introduces an implementation approach for adapted technologies as well as a comprising technical and economical assessment of the plant’s operation.
Keywords: Water supply; Hydropower; Pump as turbine; Adapted technology; Capacity development

To support the implementation of the IWRM-Indonesia process in a water scarce and sanitation poor region of Central Java (Indonesia), sustainability assessments of several technology options of water supply and sanitation were carried out based on the conceptual framework of the integrative sustainability concept of the German Helmholtz association. In the case of water supply, the assessment was based on the life-cycle analysis and life-cycle-costing approach. In the sanitation sector, the focus was set on developing an analytical tool to improve planning procedures in the area of investigation, which can be applied in general to developing and newly emerging countries. Because sanitation systems in particular can be regarded as socio-technical systems, their permanent operability is closely related to cultural or religious preferences which influence acceptability. Therefore, the design of the tool and the assessment of sanitation technologies took into account the views of relevant stakeholders. The key results of the analyses are presented in this article.
Keywords: IWRM; Indonesia; Water supply; Sanitation; Technology assessment; Sustainability assessment; Stakeholder involvement

Karst aquifers are important water resources but highly vulnerable due to their heterogeneous and complex characteristics. Various hydrological aspects (recharge, flow behaviour) have to be known in detail to develop a sustainable concept for water collection, distribution and treatment. In the karst area of Gunung Sewu (Java, Indonesia) such a concept was to be implemented within a German–Indonesian joint IWRM project. The basic hydrogeological conditions and water quality aspects were characterized on a regional scale through hydrochemical monitoring of springs, wells, subsurface and surface rivers. More detailed information about the recharge, flow and storage behaviour was obtained from high resolution monitoring of T, EC and discharge in one large underground river system. The water quality is well below any guideline values with regard to inorganic pollutants during dry season. During rainy season, dissolved Al concentrations are frequently above the Indonesian guideline value. Slow matrix flow is the most important recharge component during dry season, thus assuring the year-round water availability in the subsurface karst. During rainy season, quick infiltration of the surface water is a dominant recharge component. Rapid response of discharge, T and EC to heavy rain suggests the presence of point recharge that feeds a highly karstfied conduit system with fast conduit flow and short transit time of water. The strong variations in discharge and hydrochemistry are particularly challenging for technical water usage and treatment facilities. Piston flow is indicated to be the third important flow component and is induced by heavy rainfall.
Keywords: Karst hydrology; Groundwater quality; Electrical conductivity; Gunung Sewu; Gunung Kidul; Indonesia

Drinking water treatment for a rural karst region in Indonesia by K. Matthies; C. Schott; A. K. Anggraini; A. Silva; R. Diedel; H. Mühlebach; S. Fuchs; U. Obst; G. Brenner-Weiss (309-318).
An interdisciplinary German–Indonesian joint research project on Integrated Water Resources Management (IWRM) focused on the development and exemplary implementation of adapted technologies to improve the water supply situation in a model karst region in southern Java. The project involving 19 sub-projects covers exploration of water resources, water extraction, distribution as well as water quality assurance, and waste water treatment. For the water quality assurance, an appropriate and sustainable drinking water treatment concept was developed and exemplarily implemented. Monitoring results showed that the main quality issue was the contamination with hygienically relevant bacteria. Based on the gained results, a water treatment concept was developed consisting of a central sand filtration prior to the distribution network, a semi-central hygienization where large water volumes are needed to remove bacteria deriving from water distribution and a final point-of-use water treatment. This paper focuses on the development of a central sand filtration plant and some first analysis for the development of a recipe for the local production of ceramic filters for household water treatment. The first results show that arsenic and manganese are leaching from the filters made of local raw material. Though discarding the first, filtrates should be sufficient to reduce arsenic and manganese concentration effectively. Moreover, hydraulic conductivities of filter pots made of 40 % pore-forming agents are presented and discussed.
Keywords: Tropic karst aquifer; Water treatment; Appropriate technology; Slow sand filtration; Ceramic filtration; Point-of-use