( 7 ) 



X. Iii some rivers, as the Irrawadi or the Indus, a 

 „..,,. rather different state of things is 



How rivers have their seasons Lt . o . 



of inundations, flood the country, perCClVed. In the latter T1VGT its 



and fill lakes or tanks termed „ reatest height 18 ahoilt AugUSt. and 



Eens in Burma, and D hands o > • i /» i • r» 



in portions of the Panjab and in tlllS IS the period 01 heaviest floods ; 



Smd- in September its subsidence is usually- 



very rapid, zero being commonly reached by November. As 

 a large tract of country becomes inundated during these 

 periods of floods, the tanks, to wherever they extend, receive a 

 fresh supply of water : in Burma, where this occurs, due to 

 the risings of the Irrawadi or Pegu rivers and the downpours 

 of rain, these tanks are termed Eens, whilst in a portion 

 of the Panjab and in Sind, where the Indus extends, the local 

 term Dlidnd is employed. 



XI. These tanks or dhdnds in Sind, that are useful to 



Dhdnds or tanks in Sind main- HsllOnneU, _ are of tWO claSSeS I the 

 ly divisible into isolated ones, in first arc isolated dlldllds, and ill 



So^roSd^iZiK which communication wit li the Indus 



tions, and connected ones, which Olllv OCCUl'S during periods of illim- 



are extensions of running water f ] n f; ni1 Q nn f ] mnsflv HripQ nn winv tn 

 into a tank, and their communi- UailOllS, dllU lllOSliy Ul ILh lip pilOl TO 



cation continues throughout or tllC next year's Slipplv ; whilst the 



for the most part of the year. ^C<m& HYG COMlCCtcd d/ldiids, being 



expansions of a river, small stream, or canal into a tank, and 

 which, throughout or for the most part of the year, are con- 

 nected with running water. Some of these dhdnds are 

 without, others within, embankments, which have been 

 constructed for keeping the inundation water within due 

 limits, or bunding it in certain desired directions. 



Irrigation "Works. 



XII. Amongst the artificial causes affecting fisheries 

 are anicuts, weirs, or bunds constructed for the purpose 

 of irrigation or working mills. Irrigation weirs have been 

 erected across various rivers in the Panjab, North- Western 

 Provinces, Bengal, and Madras, in order to deflect a certain 

 amount of water iuto canals constructed for its reception 

 and dissemination. These weirs are usually built in the 

 form of stone walls across the entire breadth of rivers, 

 and consequently form an obstruction, arresting the up- 

 ward and downward passage of fish that are endeavouring 

 to migrate, whilst, should it be sufficiently high, it entirely 

 prevents their passing. On the bed of the river in front 

 of it, or on its down-stream face, there is generally a stone 

 pavement termed "an apron," or this apron may be a gradual 

 slope of rough or smooth stones extending from the summit 



