DyRes System

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Introduction

The world today faces enormous challenges in redesigning and rebuilding water systems, wastewater plants and infrastructure in general. Major investment is required to renew and upgrade these aging systems to adopt for rapidly growing population, whose future is affected by uncertain changing climate and natural disasters (e.g. earthquakes). Over the last few decades we have been witnessing many catastrophic hazardous events (e.g. floods, droughts) that have considerably exceeded the largest foreseen events and caused billions in damage. For example, floods in Europe have affected more than 1,100 fatalities and 3 million people in the period 1998-2009, with direct lost estimated as EUR 60 billion. The European Commission has estimated that, at least 17 % of its territory have been affected by water scarcity to date and put the cost of droughts in Europe over the past thirty years at EUR 100 billion. In addition, it has been estimated that earthquakes are responsible for about 35% of the economic losses generated by natural disasters.

To manage impacts of natural disasters we propose the use of system approach to enhance the predictive power in resilience assessment of water, environment, and infrastructure systems beyond the largest recorded events. The main objective of the proposed research is the development of a modelling framework for dynamic resilience assessment. The traditional risk-based approach and use of standards will be replaced with a quantitative assessment of the dynamic resilience. By developing a novel framework, the research therefore makes a context introducing a dynamic resilience as a measure for risk assessment. In this context, the research will provide the generic methodology and tools for hydroenergy, infrastructure, and environmental dynamic resilience assessment. This framework offers an opportunity for highlighting the role of using multi-model simulations which will support the estimation of dynamic resilience. It will underpin investment decisions within the different sectors (e.g. water, hydroenergy, environmental sectors) for adaptation schemes under the uncertain changes in our environment (e.g. variable climate, natural disasters).

Case study

The upper basin of the Nišava river is selected as a flood-prone area in southeast Serbia. The snow-related processes have an impact on the hydrological regime for regions with higher altitudes within the Nišava river basin. In this region, the Pirot water system is located, having catchment an area of around 571 km2. It represents a multipurpose complex system including the Zavoj reservoir at the Visočica river, hydraulically connected by a pressure tunnel equipped with hydropower plant (HPP) Pirot with the Nišava river.

The primary purpose of the Pirot water system is hydropower generation. In addition, this water system is used for mitigation of floods at the Nišava river and downstream water quality control at the Temska river by regulation of the outflows over the low-flow season. The management of the Pirot water system depends on the actual volume of water stored in the reservoirs, inflows and energy demand.

Table 1. The characteristics of the Zavoj reservoir in the Pirot water system.

Reservoir Year Built Drainage Area (km2) Annual Inflows (m3/s) Active Volume (106m3) Flood Storage Volume (106m3) Minimal Operational Level (m.a.s.l.) Spillway Capacity (m3/s) Spillway Crest Elevation (m.a.s.l.)
Zavoj 1990 571 6.2 140 5.5 568 1820 606

Goals

There are three major issues related to the reservoir operation of the Pirot water system which will be addressed by the proposed research:

  • Assessment of hydroenergy generation resilience under an extraordinary disturbance – caused by an earthquake or extreme hydrological event. For example, failure of spillways gates, pressure tunnel, data acquisition system, damage caused by floods or similar.
  • Assessment of the infrastructure resilience within the flood prone area alongside the Nišava river stream, by controlling the outflows from the Zavoj reservoir.
  • Improvement of the water quality conditions of the Temska river reach and Zavoj reservoir using resilience as a criterion and considering the emerging ecological problems in this karst region during the low-flow seasons.