Water is the source of life。Human survival and development，Can’t live without water，Development of water、Utilization and Management，Always accompanying human society。In ancient times，The ancestors mainly used water、Use it and avoid it。But about 10,000 years ago，With the emergence of settled life and the emergence of primitive villages，bet365 free bets becomes an important aspect of water management and water use。Especially after the creation of cities，Urban bet365 free bets has become an important factor in combating rain damage、An important means to control floods。So，The design and construction of bet365 free bets facilities and bet365 free bets systems have become a key part of preventing and controlling urban floods。Urban bet365 free bets facilities and bet365 free bets systems from my country’s prehistory to the Qin and Han Dynasties，There are few historical records，However, relevant archaeological discoveries and research can initially reveal its development and evolution trajectory。

■bet365 free bets culvert No. 3 in the ancient city of Qi, Linzi (photographed from east to west) Author/Photo provided

　　Prehistoric period: initial formation of bet365 free bets facilities

In our country，The origin of the city can be traced back to the end of prehistoric times around 5,000 years ago。One of the outstanding features that distinguish cities from ordinary rural settlements，is the relative concentration of the population。In terms of its physical form，A prominent feature of the early cities was that they were surrounded by walls、There is a moat outside the city wall，Form the so-called "city"，This has also become a basic tradition in the construction of ancient cities in my country。Surrounded by such a wall、In a closed space with a relatively concentrated population，bet365 free bets facilities and bet365 free bets systems have become the basic means to prevent and control urban floods。

City sites from the end of my country’s prehistoric era are widely found in the Hetao area of ​​the Inner Mongolia Plateau in the north、The Lianghu Plain to the middle reaches of the Yangtze River in the south、Starting from Shandong Peninsula in the east、Within the vast area from the Sichuan Basin to the upper reaches of the Yangtze River in the west，More than 50 have been discovered so far，Most of them date from the late Yangshao period and Longshan period between 5000 and 4000 years ago (Ren Shinan's "Investigation of Prehistoric City Sites in China"，"Archaeology" Issue 1, 1998)。

The physical form of prehistoric city sites in various places often differs due to differences in local natural environment and cultural traditions，But in terms of site selection and layout structure，The concepts of making it easier to obtain and use water and conducive to preventing and controlling floods are basically the same。As far as the middle and lower reaches of the Yellow River are concerned，Prehistoric city sites are generally located on elevated terrain on river mesas or plains。Such as Zhengzhou Xishan City Site、Dengfeng Wangchenggang City Site、The Ziya city site in Zhangqiu, Shandong and the city site built on the higher "Qudui" in western Shandong, etc.，The location selection undoubtedly takes into account the convenience of water，Pay attention to preventing and controlling floods。

　Because of this，There are many prehistoric city sites that were affected by the later swings or flooding of rivers，Partially destroyed。The plan shape of city sites is mostly square or rectangular，Surrounded by rammed earth walls，There is a moat outside the city wall。Most of the trenches are dug manually，The width often varies depending on the city site，5-7 meters is the most common，Some moats partially make use of natural rivers。Generally believed，The functions of city walls and moats are mainly defense，But from the perspective of urban water conservancy，Accept urban bet365 free bets and drain it，Should be another main function of the trench，An integral part of the urban bet365 free bets system。

bet365 free bets facilities in prehistoric city sites have been found in many places，There are ground bet365 free bets ditches、Ceramic bet365 free bets pipe、Underground bet365 free bets culverts and other types。Ground bet365 free bets ditches are the most common，Such as the Chengtoushan City Site in Li County, Hunan，Discovered the ditches used for bet365 free bets on both sides of the road during the Qujialing Culture period。While excavating the Dinggong City site in Zouping, Shandong Province and clearing out pottery bet365 free bets pipes，A bet365 free bets facility from the Longshan Culture period was also excavated and cleared near the north gate in the middle of the north wall of the outer city，Pass through the bottom of the city wall，Directly leading to the trench outside the city。The cross-section of the bet365 free bets facility is nearly square，Roughly processed wooden pillars are erected on both sides as supports，Top covered with dense logs，The bottom is paved with soil and broken pottery pieces and rammed (Luan Fengshi, "Ding Gong Longshan")、Yueshi Cultural Ancient City》，"A Survey of the Ancient Cities and Ancient Countries of Shandong"，Cultural Relics Press 2016 edition)。This is the earliest wooden structure bet365 free bets culvert seen in my country so far。

A variety of bet365 free bets facilities and a preliminary complete bet365 free bets system were discovered at the Pingliangtai City Site in Huaiyang, Henan，Its date is about 4300 years ago。Pingliangtai City Site is square in plan，A gate was found on the south and north walls respectively；A large number of row houses with adobe walls built on rammed earth foundations were found in the city，There are vertical and horizontal bet365 free bets ditches on the outer edge of the high-rise terraced houses and on both sides of the road；A group of ceramic bet365 free bets pipes were found in the west of Changpai House，Connected to the north-south road ditch on its west side；Three pottery bet365 free bets pipes arranged in an inverted "pin" shape are buried under the doorway of the South City Gate，Through the city walls and gates from underground，Connected to the road ditch and underground pottery bet365 free bets pipe in the north，To the south leading to the moat；Ceramic water pipe has a circular cross-section，Each section is 35-45 cm long，Diameter ranging from 23 to 32 cm，One end is thick and the other is thin，Jie Jie Tao Kou (Henan Provincial Institute of Cultural Relics and other "Henan Huaiyang Pingliangtai Longshan Cultural City Site Test Excavation Briefing"，"Cultural Relics" Issue 3, 1983)。This is the earliest urban bet365 free bets system known to date in my country。

　　　，Cities at the end of prehistoric times in my country initially formed bet365 free bets ditches through the ground、Underground bet365 free bets pipes and bet365 free bets culverts under city walls and other bet365 free bets facilities，The urban bet365 free bets system that discharges rainwater and daily production and domestic wastewater into the trench outside the city wall，Laid a solid foundation for the further development of urban bet365 free bets facilities and bet365 free bets systems in the historical period。

　　Xia, Shang and Zhou Dynasties: Pay equal attention to site selection and bet365 free bets

Urban bet365 free bets facilities and bet365 free bets systems during the Xia, Shang and Western Zhou dynasties，Building on prehistoric times，Ground bet365 free bets ditches that have appeared in prehistoric times、Underground bet365 free bets pipes and bet365 free bets culverts passing through the city wall，Found in city ruins in various places。Excavation outside the west wall of the No. 2 palace building foundation at Erlitou Xiadu Site in Yanshi, Henan Province revealed an exposed ditch used for bet365 free bets in the palace area。bet365 free bets facilities discovered in the palace area of ​​Yanshi Shopping City site，There are a large number of "interconnections，Small simple exposed ditches or stone ditches that constitute a "network bet365 free bets system"，There is also an underground stone bet365 free bets culvert buried in the rammed earth foundation，There are also large stone exposed ditches between the palace courtyards，And bet365 free bets culverts with stone or wood-and-stone structures that pass through palace walls or city walls ("Chinese Archeology·Xia and Shang Volume" by the Institute of Archeology, Chinese Academy of Social Sciences，China Social Sciences Press 2003 edition)。

In Zhengzhou Mall、Anyang Huanbei Mall、Anyang Yin Ruins、Pottery bet365 free bets pipes have been found at the Fenghao Zhoudu Site in Xi'an and the Zhouyuan Site in Baoji，It can be seen that it was a bet365 free bets facility commonly used at that time。Among them，The round pottery water pipes found in Anyang Yin Ruins come in various shapes，A socket-type drain pipe with a thick end and a thin end，The other is a flat-mouth butt-jointed ceramic water pipe with flush pipe openings at both ends，There is also a T-shaped three-way pottery water pipe joint ("Pottery water pipes and stone chimes unearthed from Yin Ruins" by the Anyang excavation team of the Institute of Archeology, Chinese Academy of Sciences)，"Archaeology" Issue 1, 1976)。This kind of ceramic water pipe joint is also the oldest tee joint seen in my country so far。

Spring and Autumn and Warring States Period，With the climax of city building activities，Urban bet365 free bets facilities become more diverse，Lu Ming Ditch、Ceramic bet365 free bets pipe、bet365 free bets culverts and other types of bet365 free bets facilities have been found in the ruins of capitals in various countries，The urban bet365 free bets system is further improved。Pottery bet365 free bets pipes from the middle and late Warring States Period discovered at the foundation of the palace building at the Imperial City site of the Eastern Zhou Dynasty in Luoyang，Existing single pipeline，There are also double pipes with parallel pipes；Ceramic water pipes come in both lengths and lengths、Straight pipes of varying thicknesses，There are also curved two-way pipes。Under the palace wall of the Korean Palace Castle ruins in the northwest of Zhenghan Ancient City in Xinzheng，A pentagonal pottery water pipe from the late Warring States Period that passed through the wall was excavated and cleared，This is also the earliest known pentagonal pottery water pipe (Cai Quanfa "Discovery and Research of the Ancient City of Zheng and Han"，"The Origin of Chinese Capital"，Henan People's Publishing House 2012 edition)。

Many circular pottery water pipes and bet365 free bets ditches were discovered in the ruins of the ancient city of Zhaodu in Handan, Hebei Province，Inside the walls of the East City, West City and Dabeicheng of King Zhao City，It was also found that it was laid on the slope of the city wall、Dustpan-shaped pottery trough used for city wall bet365 free bets，This kind of bet365 free bets channel is the only one seen in Handan City, the capital of Zhao Dynasty (Duan Hongzhen's "Research on Handan City, the Capital City of Zhao"，Cultural Relics Publishing House 2009 Edition)。In Xianyang City, the capital of Qin, Shaanxi，bet365 free bets facilities are located throughout the city and have various structures。Ceramic water pipes are the most common，Ceramic water pipes are available in round straight pipes，There are also curved elbows，There are also a small number of pentagonal straight tubes。bet365 free bets pipes made of ceramic water pipes are buried deep underground，With single tube、Double-tube parallel and four-tube parallel etc.。In addition，Underground pipes made of plate tiles or tube tiles were also found、Use tiles to pave the exposed ditch or bet365 free bets ditch at the bottom of the ditch，And rainwater well、bet365 free bets pools and other bet365 free bets facilities (Shaanxi Provincial Institute of Archeology "Archaeological Report of Xianyang, Capital of Qin"，Science Press 2004 edition)。

In terms of the urban bet365 free bets system during the Warring States Period，The discovery of the ancient city of Qi in Linzi, Shandong is the most complete。Linzi City, the capital of Qi during the Warring States Period，Consists of a nearly square city and a small city embedded in its southwest，Area of ​​15 square kilometers，Zihe River in the east，Xiyi Department of Water，There are trenches in the south and north of the city，The terrain is generally higher in the southeast、Northwestern low，By natural river、The moat and the ceramic water pipes in the city、Small ditch、bet365 free bets canals and bet365 free bets culverts, etc.，Constitute a complete bet365 free bets system (Shandong Provincial Institute of Cultural Relics and Archaeology "Linzi Qi Ancient City"，Cultural Relics Press 2013 edition)。

among them，Ceramic water pipes have round straight pipes、Triangular straight pipe and other types，There are also bet365 free bets pipes fastened with tiles。Small ditches are mostly dug and constructed，Some use stones to pave the bottom，Mostly distributed among various construction areas。A road with a total length of about 700 meters was found in the northwest of the small town、20 meters wide、A main bet365 free bets channel about 3 meters deep，The ends are connected to the bet365 free bets culverts in the northern section of the west wall and the western section of the north wall respectively，The moat leading to the north of the city and the water system to the west of the city，The bet365 free bets system that makes up the small town。Three main bet365 free bets channels were found in the east of Ayutthaya，The ends are connected to the bet365 free bets culverts of the east city wall and the north city wall respectively，The bet365 free bets system that forms the eastern part of Ayutthaya。A north-south direction was discovered in the west of Ayutthaya、The branching bet365 free bets channel in the northern section，Total length 2800 meters、30 meters wide、More than 3 meters deep，The ends are connected to the bet365 free bets culverts in the western section of the north wall and the northern section of the west wall respectively，The bet365 free bets system that forms the western part of the city。Among them，No. 3 bet365 free bets culvert located in the northern section of the west wall，It is a large bet365 free bets facility built with stones，By water inlet、It consists of three parts: the water crossing channel and the water outlet channel，Total length 42 meters，Width 7-10.5 meters，About 3 meters deep。15 interlaced square water holes are constructed with stones in the water channel，Water can flow out from the gaps between the stones in the hole，But people cannot pass through the water holes，The ingenious structure is breathtaking (Linzi Ancient City of Qi Ruins Museum "bet365 free bets System of Linzi Ancient City of Qi"，"Archaeology" Issue 9, 1988)。In a nutshell，Standing water around large buildings and in courtyards，Through underground bet365 free bets pipes and small ditches into the main bet365 free bets channel，The main bet365 free bets channel passes through the bet365 free bets culvert under the city wall，Direct the accumulated water into the moat or river outside the city，It can be said to be a representative of the design and construction level of urban bet365 free bets systems at that time。

In summary，Urban construction during the Spring and Autumn Period and the Warring States Period，Not only pays attention to urban location selection, "it must be above Guangchuan if it is not under the mountains"，The height is not close to drought but there is enough water，Don’t go near the water and be careful in ditches” ("Guanzi Riding a Horse")，At the same time, we also pay attention to urban bet365 free bets，"The inside is written by Luoqu，Because of the great rivers, it is infused with water" ("Guanzi·Du Di")，Accumulated experience for later city construction，Provides reference。

■Underground ceramic bet365 free bets pipes near the south gate of Huaiyang Pingliangtai City Site (photographed from south to north) Author/Photo provided

　　Qin and Han Dynasties: the bet365 free bets system became increasingly perfect

Qin and Han Dynasties，Urban bet365 free bets facilities and bet365 free bets systems are further developed and improved。Currently，Among the more than 600 Qin and Han Dynasty city ruins discovered by archeology across the country，Various bet365 free bets facilities are found in most places，Most of its types and structures are a continuation of the Warring States Period (Xu Longguo's "Archaeological Research on Qin and Han Cities"，China Social Sciences Press 2013 edition)。Among them，Most types of bet365 free bets facilities、The most complete bet365 free bets system is Han Chang'an City, the capital of the Western Han Dynasty。

The bet365 free bets facilities discovered in Xi'an Han Chang'an City mainly include indoor water collection and bet365 free bets facilities、Yard bet365 free bets facilities、Rainwater well、bet365 free bets pipe、Lugou、bet365 free bets ditches and moats, etc.，And thus constitute a complete bet365 free bets system。Indoor water collection and bet365 free bets facilities，Mainly found in buildings with special functions，Such as bedroom and bathroom buildings, etc.，There are small bet365 free bets ditches and brick pools, etc.，The end is connected to the underground ceramic water pipe that passes through the building wall。Water collection and bet365 free bets facilities in the courtyard，Mainly composed of rainwater wells and underground ceramic bet365 free bets pipes，The rainwater well may be a deep circular well with a ceramic well circle，Or a square pool made of bricks。Ceramic bet365 free bets pipes are mainly round and pentagonal straight pipes，There are also curved pipes with circular cross-sections，According to the size of the displacement，In single row、Double row、Three rows、Four rows and five drain pipes are constructed into bet365 free bets pipes。Trenches are dug and built on both sides of the road，To drain rainwater on and near roads，The ditches on both sides of Anmen Street，More than 2 meters wide，More than 1 meter deep。The road ditch is connected to the bet365 free bets ditch between each construction area，The end is connected to the bet365 free bets culvert under the city gate，Drain the accumulated water in the city to the moat outside the city。

bet365 free bets ditches are found in large numbers between the buildings in the palace building area，Among them，Small bet365 free bets ditches are often built with bricks，Some are open ditches，Some are brick culverts；The bet365 free bets ditch between the courtyards is slightly larger，Mostly exposed ditches，But when passing through the courtyard wall, underground ceramic water pipes are often used。Construction Areas and Streets、The bet365 free bets ditches between the city walls are relatively large，There are both open ditches and culverts，It is a large bet365 free bets channel in the city，The brick culvert under the No. 7 building site of Rugui Palace No. 3，Inner diameter height、The average width is about 1 meter。Under the city gate，Often built with brick bet365 free bets culverts，The inside and outside are connected to the bet365 free bets ditches inside and outside the city respectively，Drain the accumulated water outside the city，And finally discharged into the moat。For example, the culvert under the south gate of Zhicheng Gate in the middle of the west city wall is paved with bricks and stones、Brick roof structure with mother-and-son brick roof，Inner diameter width 1.4 meters、High 1.33 meters，Maximum bet365 free bets section reaches 1.8 square meters。

The various bet365 free bets facilities mentioned above are interconnected、Mutual matching，Constitutes a complete bet365 free bets system: rainwater in the courtyard is collected and discharged through underground bet365 free bets pipes；Rainwater around buildings or between construction areas，Drain into road ditches or large bet365 free bets channels through exposed ditches and underground bet365 free bets pipes；Water from road ditches and main bet365 free bets channels，bet365 free bets outside the city through underground bet365 free bets culverts near the city wall or city gate，Finally drained into the city moat through the bet365 free bets ditch outside the city。Obviously，The urban bet365 free bets facilities and bet365 free bets system of Han Chang'an City are quite developed、Quite complete。

It can be seen from this，Our ancestors went back to the birth of the city more than 5,000 years ago，Started the exploration and practice of designing and constructing urban bet365 free bets facilities and bet365 free bets systems；Urban bet365 free bets facilities and bet365 free bets systems originally started from simple bet365 free bets ditches and underground pottery bet365 free bets pipes，Continuous development and improvement since then，The Spring and Autumn Period and the Warring States Period were relatively mature and complete；In the Western Han Dynasty more than 2,000 years ago，Represented by the capital city of Han Chang'an，Urban bet365 free bets facilities and bet365 free bets systems tend to be improved，Reached a very high level of design and construction。The evolution trajectory of urban bet365 free bets facilities and bet365 free bets systems from my country’s prehistory to the Qin and Han Dynasties、Planning, design and its achievements，For the planning and construction of urban bet365 free bets facilities and bet365 free bets systems in subsequent generations and even today，Provides useful reference and historical inspiration。

　　(Author’s unit: School of History and Culture, Shandong University、Institute of Archeology, Chinese Academy of Social Sciences)