Why did water management become so difficult in June?
For the last 9 years, June rainfall has been above normal. These rains have fallen locally as short-lived very heavy rains and caused floods in major cities. This year, June rains are also falling as short-lived localized and very heavy rains, causing city floods and overflows. According to the June 2022 Temperature and Precipitation Assessment Report of the General Directorate of Meteorology, Department of Climate and Agricultural Meteorology, the areal precipitation in June in Turkey has increased for the last 9 years compared to normal.
June is generally known as a month when rainfall is normally lower than other months in Turkey. MGM calculated the long-term normal for June between 1991 and 2020 as 33.6 mm. Some years are dry and June precipitation can be even 70% below this normal.
However, June precipitation has been above normal for the last 9 years. These rains fell locally as short periods of very heavy rainfall and caused floods in major cities. This year, June rains are also falling locally for short periods of time and very heavy, creating urban floods and overflows. According to the June 2022 Temperature and Precipitation Assessment Report of the General Directorate of Meteorology, Department of Climate and Agricultural Meteorology, the areal precipitation in June in Turkey has increased for the last 9 years compared to normal.
In some years, this rate of increase has exceeded the norm by 69%.
In June last year, the situation was
In June 2022, precipitation in the Western Black Sea, northern Central Anatolia, Central Mediterranean, Southern and Central Aegean and around Kayseri, Malatya and Tunceli increased more than 100% compared to normal.
In June last year, some of our provinces had the highest precipitation in the last 90 years. In June 2022, the highest precipitation was realized in Bartın with 232.8 mm and the lowest precipitation was realized in Mardin with 0.5 mm. The highest June precipitation of the last 90 years was recorded in Zonguldak, Karabük, Bartın, Kastamonu and Düzce.
Region-wide precipitation increased compared to normal in all regions except Southeastern Anatolia. While the Aegean Region showed an increase of more than 100%, the Southeastern Anatolia Region showed a decrease of 58%. The Black Sea Region received the highest June precipitation in the last 90 years.
While the average number of rainy days was calculated as 6.5 days in 1991-2020, the average number of rainy days in Turkey in June 2022 was 10.6 days.
Rainfall in June this year
In Turkey, which started the first days of June with heavy rainfall this year, the rainfall is expected to continue intermittently throughout the month. Experts warn to be careful against floods, tornadoes, hail and storms, especially in the interior regions.
As we entered June, floods and floods occurred in many provinces across the country with the effect of torrential rains. The General Directorate of Meteorology issued code red warnings in many provinces almost every day.
So far in June this year, floods in Samsun, Sinop, Amasya, Çorum, Ordu and Kastamonu have caused loss of life and property
In Samsun, where the most rainfall in the last 93 years was experienced, approximately 68 mm of rain fell on June 4-6, 2023. It is stated that this figure is 1.5 times more than the last 93 years. It is stated that the amount of June precipitation in Samsun between 1929-2022 was 46.2 mm.
Meteorologists explain that this rainfall can last throughout June. In this case, for the last 10 years, June precipitation will be above normal to cause floods and flash floods. This reveals that the water management should take very serious measures, especially for sudden city floods and floods.
Between 2010 and 2021, the highest number of heavy rainfall and flood disasters occurred between 2018 and 2019. More than 300 flood disasters occurred in these years. In the last 4 years 2018-2021, flood disasters have occurred more than 200 each year.
Floods have occurred mostly in June for the last 12 years
Change in heavy rainfall and floods by months between 2010-2021
Between 2010-2021, the highest monthly heavy rainfall and flood disasters occurred in June. In the last 12 years, more than 500 heavy rainfall and flood disasters have occurred in June.
Most of the average precipitation in our country occurs seasonally in the form of fall and winter precipitation. These precipitations are usually low-intensity precipitation or snowfall, distributed over a long period of time. These precipitations also have the opportunity to percolate underground due to the dry or less moist soil. Depending on the duration and intensity of these precipitation, floods and overflows may occur. These floods, which are usually observed in rivers in autumn and winter, are called slow and flash floods by meteorologists. Flash floods, on the other hand, occur as "Flash Floods" in cities with inadequate infrastructure, which are mostly concreted and urbanized with thunderstorms in late spring and early summer when the weather warms up. These occur in large numbers and with increasing frequency. In this case, the number of flash floods we experienced in June and river floods, especially in the Black Sea and the Mediterranean, are naturally increasing.
Causes of flash city floods and river flooding
As a result of climatic variability, the number of sudden, heavy and short-term precipitation has increased in recent years. Although we are in June, we have been experiencing precipitation of this nature in many of our cities in recent years. There is also an increase in the number of unusual meteorological events such as tornadoes and hail. For the last 10 years, June precipitation has been above normal in our country. These rains cause flash floods and loss of life and property in our cities due to urbanization distortions, inadequate infrastructure, excessive concretization and the opening of houses below the water table levels for settlement. In addition, floods in rivers cause loss of life and property due to reasons such as interfering with the floodplain of the river by opening the areas on the banks of the river beds to settlement, insufficient bridge and culvert openings. Meteorologists and climatologists state that the frequency and intensity of these rains will continue to increase. Therefore, necessary precautions should be taken urgently.
Shifts in seasons
Experts argue that climate change and global warming are changing the precipitation regime, and that meteorological events such as droughts, floods, floods, storms, frost, fog, tornadoes, hail, etc. are becoming more severe and more frequent, and that precipitation and temperatures are deviating significantly from seasonal averages.
Reports prepared by international organizations indicate that global warming is moving towards the northern hemisphere and that the Mediterranean region will be the most affected.
There are also experts who argue that this may lead to changes in the periods of the seasons. As the Water Policy Association, in a study we conducted with the Statistics Department of Yıldız Technical University, we found that seasonal shifts in the amount of water flowing in Turkey are also occurring.
What should be done?
Our primary goal in managing both river floods and flash city floods should be to prevent loss of life.
The precautions to be taken regarding the floods in the streams flowing through our cities are clearly stated in the sub-basin flood management plans prepared by the General Directorate of Water Management and in the Provincial Disaster Risk Reduction Plans prepared by AFAD. What needs to be done now is for the relevant institutions to take these measures rapidly and in coordination.
Sustainable management of the risk of urban flooding is becoming increasingly difficult. We need to make our cities more resilient to both droughts and urban floods caused by the impacts of climate change. In addition, urban hydrology calculations should be redone taking into account the changing new conditions and wastewater and stormwater removal infrastructure in some risky areas should be renewed. In addition, uncertainties in local legislation regarding the construction and operation of discrete stormwater lines should be resolved rapidly.
Within the scope of nature-based ecological solutions in our cities, large green areas where rainwater can be collected and drained underground should be planned.
In our cities, buildings below the flood level face the danger of flooding even in non-extreme rainfall. For this reason, it is also important to raise social awareness, emergency rescue training and awareness-raising activities on what to do in floods. It is also important to prepare city flood hazard and risk maps and to raise awareness of those living in these areas on the emergency measures to be taken against flooding. It is important to inform the residents of the city of the heavy rainfall warnings issued by the General Directorate of Meteorology. However, in addition to this information, more detailed information on what to do in the neighborhood should be provided. During the heavy rainfall in Ankara yesterday afternoon, it was very useful for the Governorate of Ankara to inform citizens about the 7 underpasses that filled with water. Similarly, instant information should be shared about risky areas during floods.
To summarize; risk warning systems should be established in areas of high flood risk in cities. In addition, measures such as educating the public on how to behave during floods, informing them in detail during floods, increasing drainage capacity at low elevations and underpasses, building a separate system for stormwater collection and conveyance from sewerage, and keeping manholes and channels open at all times should be taken as soon as possible.
How should it be done?
Turkey has prepared many plans on water management such as Climate Change Action Plan, National Water Plan, Basin Management Plan, Basin Protection Plan, Water Allocation Plan, Drought Action Plan, Basin Flood Action Plan. However, draft laws such as the Climate Law and the Water Law have still not been enacted. In addition, we have legal and institutional deficiencies in the institutional structure that will implement these plans at the basin scale. We need to complete these as soon as possible and mitigate the risks that climate change will pose.
Our water management must get rid of its multi-headed and fragmented structure. We may have a lack of coordination among institutions in water management, especially at the basin scale. We should think about this today.
In addition, the General Directorates of Water and Sewerage Administrations of metropolitan cities, where 65% of the population of our country lives, need a new law. These institutions provide very important services such as water supply, wastewater and stormwater collection, removal and treatment to a population of 55 million. Climate change may make it difficult to provide these services as a public service, especially in cities. For this reason, these institutions and the water management institutions in other provinces should be provided with more funding and their institutional infrastructure should be strengthened. Water and Sewerage Administrations should be strengthened and restructured taking into account the New Water Law.
Bibliography:
Turkey Meteorological Disasters Assessment (2010-2021) Report Republic of Turkey Ministry of Environment, Urbanization and Climate Change General Directorate of Meteorology. Ankara
