The water sector includes managed water systems (water supply and sanitation, hydro-remediation, hydropower and industrial use) as well as natural water systems.
Climate change is expected to have a significant effect on river hydrology. For some river basin districts, total annual discharge is expected to decrease by about 10 percent over a 30-year period. Significant changes are expected in the seasonal distribution of river flow. While there will be an increase in winter and spring, summer and fall stream flows are expected to decrease. Groundwater availability is not expected to change significantly. Past and current weather events and trends, including the severe droughts and floods since 2000, have already affected the water sector with physical evidence of infrastructure deterioration due to flooding
Climate change risks and vulnerabilities related to the water sector are as follows:
- Flood and drought hazards are identified as the most significant for the water sector. Higher flood risks affect the whole country, while more severe droughts threaten areas with projected water shortages. Areas that use groundwater sources are expected to be at lower risk of shortages, given climate change projections that groundwater availability will not be affected, the projected decline in population in Bulgaria and the slow growth of industrial and agricultural activities. A high risk of shortage can be expected in areas with surface water supplies and intensive tourism activities, which are projected to increase.
- The Black Sea region appears to be most vulnerable to the risk of shortages because it uses surface water and is most visited by tourists. The poor state of infrastructure in this region adds another dimension to the increase in risk.
- The key vulnerabilities to these climate hazards (and their impact on water scarcity) are:
- Condition and preparedness of infrastructure: Overstretched, ageing, poorly maintained infrastructure and therefore highly vulnerable and, most likely, inadequate to cope with climate change
- Human, operator or user preparedness: Populations and infrastructure operators have no historical experience and lack good practices in floods and droughts and are therefore highly vulnerable
- Hydropower plants - vulnerable to drought operation
- Water services (water supply, sanitation, land reclamation) - vulnerable to drought
- The main risks to managed systems are infrastructure and service risks:
- Damage, improper operation and low-level or insufficient services
- Risks to hydropower plants due to low or high river flows
- The main risks to natural systems are damaged biodiversity, due to both floods and droughts
