Water damage, water damage prevention plan
In Hungary, the concept of water damage and prevention is defined by Act LVII of 1995 on Water Management. Water damage is the harm caused by an excess or lack of water. Water damage prevention refers to the protection against and defense from the harmful effects of water, i.e., the organized activity against harmfully too much or too little water.
Even in settlements without permanent protective structures (e.g., embankments) built for flood or inland water defense, it is necessary to organize defense against harmful waters, as well as draining the waters spread across the area due to flooding into watercourses or canals. This is called local water damage prevention.
Government Decree 10/1997 (VII. 17.) KHVM on flood and inland water defense clearly states that those obligated to carry out defense must prepare a local water damage prevention plan (defense plan) as part of their preparation against water damage.
Those obligated to conduct defense perform local water damage prevention tasks based on the defense plan. Technical data regarding local water damage prevention activities is included in the Urban Water Defense Plans.
Government Decree 232/1996 (XII. 26.) on the rules for defense against water damage specifies that defense plans must be reviewed annually by December 10 and any changes must be incorporated into the plans.
The Hungarian Chamber of Engineers, Water Management and Hydraulic Engineering Department, published a guideline titled Methodological Guide for Preparing Urban Water Defense Plans, which assists in the preparation of such plans.
The General Directorate of Water Management regularly compiles statistics on Urban Water Defense Plans based on data from the Regional Water Directorates.
Figure 1: Settlements with Urban Water Defense Plans nationwide, highlighting those settlements that are highly vulnerable to flash floods but do not have plans (based on 2023 data). (Green: having a plan, yellow: missing plan, red: missing plan in high-risk areas)
Flash Floods as high-priority risks
With the changing climate, extreme weather events that develop rapidly and have severe consequences are becoming increasingly frequent and harder to predict. One example is intense precipitation events, which can cause sudden flooding in mountainous and hilly regions. This phenomenon is referred to in international literature as a flash flood.
The General Directorate of Water Management, with the help of the regional water directorates and other experts, has developed a method that, based on both passive (e.g., topography, hydrography) and active (e.g., precipitation) factors, scientifically estimates—with reasonable accuracy—the level of risk these factors pose in individual catchments. Based on these assessments, hilly catchment areas were categorized into different hazard levels.
Figure 2. Hilly Catchment Areas of Hungary in Terms of Flash Flood Risk.
Local Water Damage Prevention Readiness
Local water damage prevention readiness can be ordered for a watercourse’s catchment area and its facilities, reservoir, or the respective municipality’s administrative area to fulfill of a specific defense task.
The defense leader (of the organization obligated to carry out defense orders) can modify or cancel the local water damage prevention readiness level for their own organization, excluding extraordinary readiness.
Level I. readiness is ordered if:
- Standby and technical duty service need to be established;
- HungaroMet meteorological forecast issues an orange (level 2) or red (level 3) warning for the area;
- According to forecasts for small watercourses, watercourse bed occupancy exceeds 80%.
Level II. readiness is ordered if:
- Hydrological forecasts predict rising or falling water levels, territorial flooding, or precipitation activity requiring territorial presence.
- Level III. readiness is ordered if:
- Forecasts for small watercourses indicate water levels approaching the bank height, with further significant rises expected;
- Temporary protective structures or other interventions are required to protect the inner areas of the settlement against flooding.
Extraordinary readiness is ordered if:
- If the water damage situation worsens, and further urgent interventions are necessary to protect life and property, and the defending organization is unable to carry out the defense with its own equipment and resources.
Point-specific level III readiness
- The defense leader is required to carry out necessary repairs in the channel, depot, municipal flood protection structure, reservoir embankment, or other facilities until completion.
Detailed regulations on ordering readiness levels and tasks to be performed during local water damage prevention are set out in Government Decree 10/1997 (VII. 17.) KHVM.
Defense Tasks
Tasks of local municipalities:
- Construction of protective structures (serving up to two settlements), maintenance, development, and defense of protective structures owned by the municipality;
- Prevention of flood damage from streams and canals within the settlement’s inner areas, as well as damage from rain and other waters by constructing and maintaining protective structures in both outer and inner areas and performing defense activities thereon;
- Performing tasks related to protection against water damage defined by separate legislation.
Tasks of water management administrative bodies (Water Directorates) related to water damage prevention:
- Direction and performance of technical and administrative duties related to water damage prevention;
- Territorial planning, organization, and professional supervision of defense;
- Professional supervision of local municipalities’ water damage prevention activities;
- Providing data for preparing and reviewing water damage prevention and development plans related to water damage prevention for local municipalities, and preparing and reviewing Urban Water Defense Plans for settlements located on open floodplains along rivers;
- Professional supervision of water associations’ water damage prevention activities;
- Providing public information related to protection against water damage.
As mentioned above regarding readiness levels, the defense leader of the obligated organization orders, modifies, or cancels the local water damage prevention readiness level for their own organization, excluding extraordinary readiness. The obligated organization immediately informs the on-duty Water Directorate and the professional disaster management authority about the ordering, changes, and measures taken regarding the readiness level. These bodies mutually inform each other about all relevant circumstances during the ordering of readiness levels and the defense process.
Figure 3. In settlements where no embankment has been constructed, temporary defense may become necessary during the defense. (Baja, Petőfi-sziget, 23/9/2024, Zoltán Jobbágy)
For protective structures maintained by settlements defending with their own organization, the technical tasks of flood and inland water defense within the administrative boundaries of the settlement are carried out by the mayor through the mayor’s office, under the professional supervision of the water management administrative body.
As part of assistance to the mayor, the Water Directorate provides technical supervision and designates protective lines for flood defense on high banks and settlements engaged in flood defense on open floodplains along rivers, and determines the construction levels of temporary protective structures.