Abstract
Providing water for the inhabitants of the plateau of Iran, which is located in the arid and semi-arid region of the earth, has always been one of the most important challenges for the its people since the beginning of the formation of the first dynasties and establishing the first irrigation systems. Low rainfall climate has caused the Iranian people to innovate different techniques to provide water for agriculture activities permanently.  Iranians are considered as the main creators of Kariz (subground aqueduct) as one of the most practical methods of exploiting underground water resources. Exploitation of running water resources by construction of dams on rivers and springs and the creation of canals is another method rooted in the history of the civilizations of the west Asia for supplying more sustainable water for the agricultural and industrial functions. In the specific and under investigation area of the Pulvar River, where the Achaemenid capital of Pasargadae is located, there are some of the ancient water structures including dams, artificial waterways, canals, extensive water reservoirs and springs. Of theses the dams are mostly built on the tributaries of the Pulvar River, and the water supplying canals are located below them.  Such complex structures have been built in the plains and districts surrounding Pasargadae such as Didegan, Murghab, Sarpiran, Kamin and Arsanjan. The present investigation briefly introduces these water structures and the techniques they were made in the Achaemenid period in the cultural landscape of Pasargadae. The results of this research are based on the studying historical documents and field studies of the past decades by historians and archaeologists, as well as field surveys by the author during the recent years in an area of nearly 16,000 square kilometers. The results of this research are amazing and very impressive. These extensive water systems, with the tact and intelligence of Achaemenid managers and engineers, have supplied water to all the plains and mountain valleys of the Pasargadae region. Villages and public settlements, gardens, agricultural lands, government buildings and centers, and finally the Royal Paradise of Cyrus the Great used of the benefits of water supply structures. In the construction of the dams, clay materials and ashlar or carved stone masonries have been applied, and some of them also have architectural structures with cut stone blocks. Waterways are also created in several ways on the slopes of hills and rocks.  Studies and researches show that the construction of water structures in the study area began during the reign of Cyrus the Great and expanded during the reign of Darius the Great and continued to develop until the end of the Achaemenid period. This method of exploiting surface of sub ground water resources continues to post-Achaemenid periods, especially in the Sassanid era and continues till modern times.
Keywords: Historical Dams, Achaemenid Architecture, Ancient Irrigation, Pasargadae, Achaemenid Empire.

Introduction
It is for the first time that in this era, a tremendous transformation in Iranian architecture occurred by mixing the traditions of architecture and art with the traditions of other nations that came under the umbrella of the Achaemenid government. The builders of Pasargad, in order to establish a new capital that can have a correct concept of a powerful and magnificent government center and also bring the comfort of its residents, beyond the plain of Pasargad, investigated and assessed the feasibility of all the surrounding plains , and after That Pasargad was designed and built What can be concluded from these structures is that Pasargad was not limited to the complex of royal buildings whose remains remain in the center of the Pasargad plain, and it correctly had the concept of an official and advanced capital. A wide range of infrastructures that a government center like Pasargad needs has been identified in a wide area of Pasargad plain and the surrounding plains, which is a proof of how Pasargad was built and founded. An important part of the aforementioned infrastructures is the vast collection of water structures that were designed and built in the ancient territory of Pasargad. One of the most important plans of the Achaemenid government was to deal with the water issue, which the Shah and the administrative organization had taken over the management of (Brian, 1985: 1985). In the upcoming research, an attempt has been made to introduce the Achaemenid water structures of Pasargad region and its impact on the construction and development of Pasargad. In the 1980s and 1990s, the Pasargad World Heritage Site also conducted a field survey in the Pasargad Plain and the surrounding plains (Karami and Zarei 2015), and in this research, several dams and extensive water supply networks were identified (Map 1). In the fall of 2019, from the first season of the exploration of Didegan Dam (Bostan Khani) was done and parts of the architectural structure of the dam and its wall and foundation were explored and researched, which resulted in valuable results (Karami, 2019, unpublished).

Introduction of Water Structures and Their Function
The extent and variety of Achaemenid works and sites in the territory of the Achaemenid Empire shows the intelligence and management ability of the Achaemenid government in the administration of the country in all fields, looking at the capabilities of the territory and the environment and paying attention to the culture and social capital of the various regions of the empire, which can be seen in He searched for historical documents and remains of Achaemenid works and sites.

The Effort to Manage the Country is More Visible in the Important Achaemenid Centers
In Pasargad, which is our focus in this research, various aspects of art and culture, architecture, government infrastructure, engineering and public settlements have been revealed and can clarify some of the unknowns. Whenever the name of Pasargad is mentioned, the collection of royal buildings and especially the tomb of Cyrus, the founder of the Achaemenid Empire, is remembered in our thoughts. But the Achaemenid capital of Pasargad is much wider and beyond the current area What we see today is the result of the knowledge and efforts that the engineers and builders of Pasargad have applied in a wide area of this area and have created a set of structures and infrastructures that meet the needs of the ruling center of Pasargad. One of the most important remaining infrastructures is the set of water structures that were created in the ancient landscape of Pasargad in several plains centered on Pasargad. However, metal and building stone quarries, metal smelting workshops, road networks, bridges, security checkpoints and support centers are other parts of the infrastructure works in Pasargad (Karami & Zarei, 2015). The concept of the ancient landscape of Pasargad can be considered for all the hills and heights around Pasargad, where the Achaemenid works and sites are directly related to the government site of Pasargad. The extent of this ancient area can be considered to be nearly 16,000 square kilometers based on archaeological surveys and researches, which according to country divisions includes the cities of Euclid, Khorrambid, Bowanat, Sarchehan, Pasargad, Arsanjan and Maroodasht from north to south.Pelvar River is the only permanent river in this area, the formation of settlement patterns of the first settlements from the Middle Paleolithic period until now is dependent on this river (Map 2).

Conclusion
The historical water structures of Pasargad and Persepolis are among the most prominent and valuable works left over from the Achaemenid era, which are located in the Bakhtegan and Tashk watersheds. The two main catchment rivers, Pelvar and Kor, form one of the basins in which the water from the rains in the highlands and plains flows into them in the form of flowing water and under the surface.  Due to the presence of two important Achaemenid centers of Pasargad and Persepolis in this basin and the need to provide water for them in the headwaters of these rivers, especially the Pelvar River, several reservoirs and diversion dams have been built with the aim of exploiting surface water resources And extensive waterways and water supply networks have also been established These structures include dams, waterways and water distribution networks, springs and reservoirs, and stone architectural structures for water distribution. The embankments are made of earth in the form of a hard clay core and a shell of stone debris and are mostly built on the heads of the branches, and the water roads are also on the slopes of Mahori hills and rocks and in the middle of the plains with two methods of accumulating soil and stone debris and excavating And the cutting of rocks has been created It seems that the Achaemenid engineers have selected the best and most efficient places for the construction of dams after investigating and studying the field of this basin. The mouth of mountain gorges through which seasonal rivers pass is the best place to build a dam Because the stone body of the valleys makes the dams stable and durable, and it has been easier and more reliable to contain and store the floods in the sub-branches. Due to the extent and shape of the catchment of this basin, the Pelvar river floods during rains and a large amount of water enters it, and it was not possible to control it for the Achaemenid engineers considering the facilities and technology of that era. Therefore, the best option for flood control is the construction of dams at the head of the branches and tributaries of Pelvar Also, it is easier to transfer the dams built at the head of the branches, which are located at a higher place than the plains and flat lands, and most of the downstream parts have benefited from the stored water. Apart from curbing seasonal floods, supplying water to settlements and residential areas, agricultural lands and gardens, providing water to Pasargad government grounds and especially Shahi Campus, as well as industrial uses and mills, are among the goals of building this vast complex of There have been water structures in this area The history of the construction of this set of water structures is related to the Achaemenid period, which, based on researches and archaeological documents, started from the beginning of the Achaemenid period and with the reign of Cyrus and expanded during the reign of Darius and was developed, maintained and exploited until the end of the Achaemenid period.