<Tr> <Td> 1.15--1.72 </Td> <Td> 2.15 </Td> <Td> Den Helder </Td> <Td> northeastern end of Holland dune coast west of IJsselmeer </Td> </Tr> <Tr> <Td> 1.67--2.20 </Td> <Td> 2.65 </Td> <Td> Harlingen </Td> <Td> east of IJsselmeer, outlet of IJssel river, the eastern branch of the Rhine </Td> </Tr> <Tr> <Td> 1.80--2.69 </Td> <Td> 3.54 </Td> <Td> Borkum </Td> <Td> island in front of Ems river estuary </Td> </Tr> <Tr> <Td> 2.96--3.71 </Td> <Td> </Td> <Td> Emden </Td> <Td> east side of Ems river estuary </Td> </Tr>

What is the name of the river which connects the city of london with the north sea