Editing Lothal (section)

==Dockyard==
[[File:Dock_at_lothal.JPG|thumb|The dock, with a canal opening to allow water to flow into the river, thereby maintaining a stable water level.]]
[[File:Mechanism to control water flow at the "Dockyard.JPG|thumb|Remains of, meter square, sluice gate, south face, built with burnt bricks.]] 
The trapezoidal, burn brick, structure is located on the east of the town and away from the main river channel, to possibly avoid deposition of silt. The north–south length averages {{convert|215|m|ft|abbr=off}}, and east–west width of {{convert|35|m|ft|abbr=off}}.<ref name="Rao2819">{{cite book
| title = Lothal
| publisher = [[Archaeological Survey of India]]
| author = S. R. Rao
| author-link = S. R. Rao
| pages = 28–29
| year = 1985
}}</ref> An inlet approximately {{convert|7|m|ft}} wide and {{convert|0.9|m|ft}} in depth survives in the north of the structure, and a {{convert|1|m|ft}} square sluice gate or spillway, that appears could have been dammed by a wooden gate, exists in the south face of the structure.<ref name=":0" /> 
When the river changed its course in 2000&nbsp;BCE, a canal approximately {{convert|7|m|ft|abbr=off}} wide and {{convert|2|km|mi|abbr=off}} long, was dug to the new river course.<ref name="Rao2819"/>

Facilitating the movement of cargo was a [[mudbrick]] [[wharf]], {{convert|220|m|ft|abbr=off}} long, built on the western arm of the dock, with a ramp leading to the warehouse and acropolis, built on a packed mud platform, original {{convert|4.26|m|ft|abbr=off}} in height (Now it is {{convert|3.35|m|ft|abbr=off| disp=or}}.) on the south western flank of the basin.<ref name="Rao5A">{{cite book
| title = Lothal
| publisher = [[Archaeological Survey of India]]
| author = S. R. Rao
| author-link = S. R. Rao
| pages = 7–8
| year = 1985
}}</ref>  The warehouse was originally built on sixty-four cubical blocks, {{convert|3.6|m|ft|abbr=off}} square, with {{convert|1.2|m|ft|abbr=off|adj=on}} passages, and based on a {{convert|3.5|m|ft|abbr=off|adj=on}} mud-brick podium. The pedestal was very high to provide maximum protection from floods. Brick-paved passages between blocks served as vents, and a direct ramp led to the dock to facilitate loading. The warehouse was located close to the acropolis, to allow tight supervision by ruling authorities. Despite elaborate precautions, the major floods that brought the city's decline destroyed all but twelve blocks, which became the makeshift storehouse.<ref name="Rao171">{{cite book
| title = Lothal
| publisher = [[Archaeological Survey of India]]
| author = S. R. Rao
| author-link = S. R. Rao
| pages = 17–18
| year = 1985
}}</ref>

Rao's identification of basin as a dock was challenged by Leshnik in 1968 and later Yule in 1982,<ref>
| title = Lothal
| publisher = [[C.H. Beck]]
| author = [[Paul Alan Yule|Paul Yule]]
| pages = 31
| year = 1982
</ref><ref name = "JSTOR"/> 
who offered an alternative assessment of the feature as primarily an irrigation tank. In their assessment the dimensions of the "inlet" are not large enough to accommodate the [[Draft (hull)|draft]] of ocean going vessels, with inland craft having to be used to ferry goods to ocean going vessels birthed elsewhere. The identification of just two wells in the town, one on the southern edge of the dock and the other on the acropolis, were also offered to support the alternative primary purpose, as a tank to irrigate vegetables in the adjoining fields, a place to bathe, and a quay to unload river boats.<ref name=":0" /><ref name="JSTOR">{{cite journal |last1=Leshnik |first1=Lawrence S. |title=The Harappan "Port" at Lothal: Another View |journal=American Anthropologist |date=1968 |volume=70 |issue=5 |pages=911–922 |jstor=669756 |doi=10.1525/aa.1968.70.5.02a00070}}</ref>

The National Institute of Oceanography, Goa discovered foraminifera (marine microfossils) and salt, gypsum crystals (due to evapouration of seawater) in the rectangular structure clearly indicating that sea water once filled the structure, though Leshnik argued these could have been left through flood events.<ref name=":0" /><ref name="researchgate.net"/>

The purpose of the 5 stone weights found around the basin, as to whether they were anchors or [[Shadoof]] weights has also been debated, as have the source of the estuarine shells from the dock,<ref>{{cite web|url=https://www.researchgate.net/figure/a-e-Types-of-stone-anchors-found-along-the-Gujarat-coast-of-India-Sila-Tripati-f-k_fig2_301522406 |title=Stone anchors of India: Findings, Classification and Significance |date=January 2014 }}</ref><ref>{{cite web|url=http://nmma.nic.in/nmma/nmma_doc/Indian%20Archaeology%20Review/Indian%20Archaeology%201961-62%20A%20Review.pdf |title=Indian Archaeology 1961-62 A Review }}</ref> 5 terracotta models of boats and a circular Persian Gulf seal from Bahrain.<ref>{{cite web|url=https://www.penn.museum/sites/expedition/shipping-and-maritime-trade-of-the-indus-people/ |title=Shipping and Maritime Trade of the Indus People |publisher=Expedition Magazine|date=1965 }}</ref>

It is speculated that Lothal engineers studied tidal movements, and their effects on brick-built structures, since the walls are of kiln-burnt bricks. This knowledge also enabled them to select Lothal's location in the first place, as the [[Gulf of Khambhat]] has the highest tidal amplitude and ships can be sluiced through flow tides in the river estuary.

The main inlet is {{convert|12.8|m|ft|abbr=off}} wide, and another is provided on the opposite side. To counter the thrust of water, offsets were provided on the outer wall faces. 
At high tide flow of {{convert|2.1|–|2.4|m|ft}} of water would have allowed ships to enter. Provision was made for the escape of excess water through the outlet channel, {{convert|96.5|m|ft|abbr=off}} wide and {{convert|1.7|m|ft|abbr=off}} high in the southern arm.

There was an important public building opposite to the warehouse whose superstructure has completely disappeared. Throughout their time, the city had to brace itself through multiple floods and storms. Dock and city peripheral walls were maintained efficiently.{{citation needed|date=August 2020}} The town's zealous rebuilding ensured the growth and prosperity of the trade.{{citation needed|date=August 2020}} However, with rising prosperity, Lothal's people failed to upkeep their walls and dock facilities, possibly as a result of over-confidence in their systems. A flood of moderate intensity in 2050&nbsp;BCE exposed some serious weaknesses in the structure, but the problems were not addressed properly.<ref name="RaoY"/>