To cater for the ever-increasing demands of water after the completion of Pok Fu Lam Reservoir, much larger reservoirs and more complex water supply systems were constructed under the Tai Tam Scheme and Tai Tam Tuk Scheme between 1883 and 1917. With improved water provision brought by the two Schemes through the construction of Tai Tam Upper Reservoir (1888), Tai Tam Byewash Reservoir (1904), Tai Tam Intermediate Reservoir (1907) and Tai Tam Tuk Reservoir (1917) (which are collectively known as Tai Tam Group of Reservoirs nowadays), the forces of urbanisation gradually spread from central and western districts to the eastern side of Hong Kong Island, thus expanding the Hong Kong urban area.