The Ouse is the chief river of this district. Its out let was formerly by Wisheach, then a very consider ible seaport. Between Wisbeach and Erith the ri‘cr 'iad two channels. viz. one on each side of the island of Ely, Of these, the Eastern, or Old Ouse ran by Ely to Lit. deport. Having received the Grant from Cambridge, and the Mildetiliall river 'rum Littleporn it passed to Wisbeach, instead of uniting-, as at pit:sent, with the Lesser Ouse, and passing. to Lynn, Tire other brunch, called the Westwater, passed from Erich to Ramsay INIcre and tiwick, where it met part of the Nen, then by. Great Cross, to meet the other branch at Wisbeach, and so out to the sea.
Thu most remarkable change on this river, was the cut front Littrepurt into the Rumden river at Rebeek. Not only the original eastern, or Ely branch, was con veyed to the sea at Lynn; but even much of toe West water and river Nen, and even part of the Welland, instead of passing to Wisbeach, ran by the Welk river to the same new cut at Littleport. It would also ap pear by the pttition from Marshland, in the reign of Edward III. that the lower part of the united Western Ouse and Nen, called the river Welk, had, at the suit of the inhabitants of the upper counties, been diverted from the original outlet at Walsoken, near Wisbeach, and carried along the larshlancl to the Ouse at Wig genhale. While, therefore the outlets towards Wis beach were rapidly silted up, nearly the whole waters of the Fen were conveyed to the haven of Lynn; which, from this cause and the increased flux and reflux of the sea, became greatly deepened and enlarged. Stre nuous efforts were made by the people of Marshland to have the Ouse narrowed, and confined between banks, as formerly ; but they were constantly opposed by those of Lynn.
The next remarkable alteration on the Ouse was Pop ham's Eau, from Upwall to Denver. Its object was to take off the Welk stream by a shorter course than that at Littleport, and more open are, direct than the old chan nel through Welle. But Bedford river, and the New Bedford, or Hundred-foot rivet, parallel to it, forming. a direct channel of 20 miles through the Fens, from Erich to Denver, was by far the greatest change to which the course of the Ouse was subjected, and, in the end, has laid dry all the upper part ef the Westwater.
Above the Fen country the Ouse river continues na vigable tu Bedford, about 84 miles front the sea. Its
various branches tvill be described hereafter.
The next river in importance and order is the Nen, navigable from the sea below Wisbeach through the Fens to Peterborough, and thence hy the regular chan nel, improved by side cuts and locks to Northampton. Below Peterborough the river seems to have spread into various lakes, as Wettlesey Mere, Ramsay Mere, Stc. ere it joined the western branch of the Ouse at Benwiek, as afore mentioned, and passed therewith to Wisbeach, as to the Ouse at Salter's Lodc by the river of Welle, Ste. Various attempts have been made to shorten the course of the Nen : Of these, the Catwater, on the north ern side, was an ancient cut to the triangular bridge at Craylancl, to unite with the Welland, and pass by Spald ing; but that outfall decaying, thc Catwatcr became useless ; and. somewhat lower down, the water s of the Welland were brought by tilt South Eau to Guyhirn, and thence back to the channel of the Nen and Wis beach, or even by tht Welk: to the Ouse.
To the south, King's Delf and Whittley Dyke are ancient cuts to shorten this river; but the most impor tant is Morton's Lem, from Peterborough to Guyhirn and NVisheach, first opened by Nloreton, bishop of Pe terborough, in the reign of Henry VII, ; since perfected by Charles I. jointly with the Bedford level adventurers. This also drains off the waters of the NVelland.
The river Welland having entered the Fens at Deep ing, passed originally to Crayland Bridge, and by Spald ing to Sarfleet, where, receiving the river Glen, it pro ceeds to the sca at the Foss-dike Wash, This river seems to have been chiefly injured by the injudicious modes employed to drain the adjacent Fens, thereby ab stracting a great proportion of its waters. A variety of plans have been suggested for changing the course of the Welland, and relieNing the district of South Hol land, viz. instead of allowing its waters to pass to the Ouse, to conduct them along the north shore to thc Witham ; and, in 175 t, Kinderby proposed to carry both the Nen and Witham nearly as far east as Wainsfleet.
But to understand the Fen navigations, we must enter at some length into the history of drainage in these very important and interesting tracts of country.