Presently, Dali Mountain Reservoir located in Dedoplistskaro Municipality, is left functionless. It has been the second year already that the Society for Nature Conservation, SABUKO is conducting activities for conservation of the gallery forest and grasslands in the Iori river valley.
Under this project, SABUKO takes the initiative to periodically flood nearby floodplain forest by discharging water from the Dali Reservoir, thus returning the existing habitat to its natural state. Studies show that the Reservoir has changed the hydrological regime in the lower part of the Iori River to such an extent that it may pose a serious threat to biodiversity.
The history of the Dali Mountain Reservoir dates back to the 80s of the last century. Normally, the construction of the second-largest reservoir in Georgia should not have been a simple project. However, as the words go, it never have seen the light of day – it never served its original purpose. Soon after the collapse of the Soviet Union, it was launched in 1992, and according to the official version, it was decided to use the reservoir for irrigation. The construction of the reservoir was aimed to settle two villages on the territory of Chachuna Managed Reserve and cultivate land for agricultural purposes. However, as hydrologist Nika Tsitelashvili tells me, in the same year when the dam was opened, the flooding happened. The water level rose so quickly that employees were frightened and decided to open the shields and empty the dam as soon as possible. However, according to the second version, the construction of the Reservoir was actually not completed. As a result: “The upper part slipped down and it is still in critical condition,” – explained the hydrologist.
For this or for unknown reasons, the Dali Reservoir has never served its purpose. Today it is sealed and its operation is limited only by regulating releases from the shields and maintaining a stable water level in the reservoir (the Reservoir is on the balance of Georgian Amelioration LLC.). Besides, one of the private entrepreneurs is licensed by the Ministry of Environment Protection and Agriculture of Georgia to use the wildlife objects until 2030, and in fact, only this private person uses it for irrigation and fishing.
Moreover, today the Dali Mountain Reservoir is called a dead zone. “A non-functional reservoir located in an open field” – this is how Gizo Chelidze, Head of the Department of Hydromelioration and Land Management of the Ministry of Environment Protection and Agriculture, describes the current state of this large-scale project.
At the end of the upper part of the Chachuna Managed Reserve, before the Reservoir, a huge bridge leads us to the beginning of headwork. This building has been abandoned for years and now is a temporary sanctuary for bird. The echoes of a team of pigeons can be heard from the half-broken glasses.
However, it is not a harmless and gently swamped reservoir with abandoned infrastructure, SABUKO researchers explain, and they speak about the hazards that a non-functional reservoir could pose to the local ecosystem and the biodiversity of the Chachuna Managed Reserve down below.
The Dali Mountain Reservoir is located below Dali Mountain, Dedoplistskaro, Kakheti. There is Chachuna Managed Reserve in its lower part, covering 5200 ha, that was established in 1996 and is extended to the extreme – south-east edge of the country, near the border of Georgia-Azerbaijan.
Along with a decrease in annual precipitations in Dedoplistskaro municipality, a significant part of the land cover in the Managed Reserve is degraded. This is caused by overgrazing and irrational use of pastures. The floodplain cover is also being decreased as sheep move further down the floodplain forest due to pasture degradation.
“The disappearance of the floodplain forest means that, for example, nesting places, nesting trees for the birds such as Black Francolin, Eastern Imperial Eagle, white tailed Eagle will disappear; and the shelters, food and water supplies for mammals that are common for this place – badgers, wild boars, porcupines, wolves, golden jackals… will also disappear.
Thus, when the shelter is narrowed down, definitely, it directly affects its existence in general” – explains Khatia Basilashvili, head of the Conservation Researches of SABUKO, presently exploring the biodiversity of Chachuna Managed Reserve.
Photo: Vakho Khetaguri, National Geographic Georgia
It was the activities that started in the Chachuna Managed Reserve that led SABUKO to Dali Mountain Reservoir, and it was the threat posed to the Chachuna Managed Reserve that led them to think about how to restore and return function to the Reservoir.
In 2019, a survey of forest health conditions in the upper and lower parts of Dali Reservoir was conducted. The recommendation of relevant field specialists was to study the extent to which the shape of the forest area was changing and whether such species of plants were introduced into the lower part of the Reservoir, which is typical for a dry desert climate.
According to the study of the organization, there is a big difference in the floristic composition of the upper and lower streams of the Reservoir. In Chachuna Managed Reserve located below the Dali Reservoir, there are many species that are characteristic of the arid ecosystem. In the upper part, there are more species typical of floodplain forest: “This may be directly related to the flooding regime and the intensity that should have changed after the commissioning of the Dali Reservoir”.
Based on the given condition and historical data, SABUKO accomplished the hydrological survey and revealed the corresponding flooding areas.
As Nika Tsitelashvili, one of the authors of the study explains, the specialists revealed that the hydrological regime has significantly changed due to the Dali Mountain Reservoir. In fact, there are no more high level of waters, no more flooding, no more solid material movement from the upper canal pound to the lower one. This in turn contributes to the valley-edge and deepwater erosion. Due to deep erosion, the riverbed has deepened and today the River can carry the maximum amount of water that can be released from the Reservoir without flooding the floodplain.
In addition, the ongoing processes were influenced by other hydraulic structures in the Iori River catchment. These are the Sioni Reservoir and the Paldo intake, which supply drinking water to the part of Tbilisi and Rustavi. Both of them are the main controlling objects of the hydrological regime and have a significant impact on the floodplain forest as well. Consequently, presently, Iori is regulated from the head to the confluence and there are no floods and high waters reported there. The movement of solid material is also significantly worsened. Besides, it follows by the non-function of the Dali Mountain Reservoir and there is virtually no significant increase or decrease in water level on the River, which has a negative impact on the ecosystem and leads to its degradation.
Thus, as per the initiative of SABUKO, negotiations were started with the Ministry of Environment Protection and Agriculture of Georgia, as well as with the Georgian Amelioration LLC. to use the water accumulated in the Dali Mountain Reservoir for compensating the changed hydrological regime on the river and for restoring floodplain forest.
How, in what quantity and on what principle? – Should the Iori River floodplain be artificially flooded and in case of water release, several aspects must be taken into account, including the fact that the river bed and bottom are already eroded. The height of the first terrace in some places reaches 1.2 meters in eroded areas. The SABUKO study states that the appropriate operation of damper is needed to reduce the water flow rate and minimize the artificial acceleration of deepwater erosion.
As for the quantity of water, hydrologist Nika Tsitelashvili explains that they wanted to release a lot more water from the beginning, however, because one shield of the reservoir is completely damaged and only the second can be opened in this condition, the maximum that can be released from the reservoir is 70 m3 /sec. This activity will be accomplished seasonally, in spring and autumn. In spring, floodplain forests will be flooded twice in 6-6 hours, with a similar intensity in the fall, which means that water will be released from the reservoir 24 hours a day for a year: “Therefore, it is desirable to release water from the dam gradually, for seeing its effects or negative impacts,” explains the hydrolo
gist; flows of tributaries should also be considered: “thus, it is desirable to coincide the water release from the reservoir to the flood of tributaries”.
70 m3/sec is not quantity that can flood the entire floodplain forest. That is why SABUKO also works in the field of hydro engineering – in order to achieve maximum results from flooding, it is desirable to arrange barriers or gabions on preliminarily selected areas, that will also reduce the speed of the river flow, raise the water level and reduce the erosion level. For this purpose, SABUKO has already submitted to the Ministry of Environment Protection and Agriculture of Georgia two places where these constructions can be arranged: “These will be 2 small buildings for which you can use stone, rocks or other inert material, which will reduce erosion. Consequently, the level in the river will rise and we will get the same effect that we normally had to have in order to flood a floodplain forest,” the hydrologist said.
We asked Gizo Chelidze, the head of the Hydromelioration and Land Management Department of the Ministry of Environment Protection and Agriculture of Georgia, for his opinion on the Dali Reservoir. He told us that the Ministry does not see any problem with the use of the already non-functional reservoir. However, he has a question – is there enough water resources in the reservoir to flood the floodplain forest?
The quantity of the Reservoir is absolutely sufficient for SABUKO to flood the Iori floodplain forests” – says Zurab Kajaia, Manager of the Georgian Amelioration projects.
As he explains, initially, the Dali Mountain Reservoir was designed for 180 million m3, whereas dead water space should have been 40 million m3 (this means that the Reservoir should be constantly holding 40 million m3 of water for avoiding subsequent dangers and cracks). However, due to the fact that the construction was not completed, the accumulation of such quantity in it is now dangerous: “As far as I know, there are 70 million m3 in the reservoir at the moment. Therefore, I can assure you that it is completely sufficient for the flooding of floodplain forests,” explained a representative of the Georgian Amelioration LLC.
Speaking about the position of the Ministry of Environment Protection and Agriculture of Georgia in general, how they see the future of the Dali mountain reservoir, Gizo Chelidze says that almost each year the question is on the agenda of the Ministry – how to deal with Dali Reservoir?
“Some say we should demolish it, others support its reconstruction. I do not have an exact answer to this question. Both of them are related to high financial resources. Demolition also requires funds, and it’s a risk to think about its reconstruction,” said Gizo Chelidze, adding that the World Bank has launched a project to study up to 30 reservoirs in Eastern Georgia.
Dali Reservoir will be among them: “This is the research that will give us answers, whether it is worth to think about the future of Dali Reservoir?” Otherwise, I lay my arms down and say that this Reservoir is already inactive, and if someone uses it for their own benefit, then on the contrary, I welcome it. But I still say that there is a lot to explore before doing that.”
Under the project “Piloting the Strategic Environmental Assessment of the Alazani-Iori River Basin Management Plan”, the recommendation of SABUKO is brought in the document – “Alazani-Iori River Basin Management Plan (RBMP) – Thematic Overview”. After analyzing SABUKO researches, various measures were developed, including restoration of natural flooding in the lower part of the River Iori, partial opening of the Dali Reservoir for the imitation of the natural flooding, as well as upgrading of Dali Reservoir infrastructure.
“All these provide the possibility to control the flooding regimen and intensity, which is important for improvement of the ecosystem of the lower part of the Dali Reservoir” – we read in the document.
Notwithstanding the fact that the reason of water releases from the Reservoir and flooding of the floodplain forest is to recover the habitat of Chachuna Managed Reserve and keeping of the biodiversity therein, there arises a question – Could this have a negative impact on the birds of prey and mammals prevalent in the area?
“It will not be water that will wash away everything. Rather, our goal is to make it flow smoothly, little by little, and seasonally, so as not to ruin the nests of the birds. As for mammals, this can be far problematic. Initially, water might reach their lairs and damage them. However, it also means that they will gradually move to the depths of the floodplain forest and thus, their habitat will expand,” says Khatia Basilashvili, head of SABUKO Conservation Researches. She also explains that the expansion of floodplain forest will also expand the habitats of species, and thus increase the number of species, which is the principal objective of all our activities.