The subject of water resources provided the greatest motivation for the growth in hydrological studies in the twentieth century. An expansion of hydrological measurements, especially in the second half of the twentieth century, was driven largely by needs for the evaluation of water resources, which initiated widespread and comprehensive study of the hydrological environment. In the UK, legislation for water dated from the Victorian era, when Acts of Parliament were passed to grant powers at a local level to provide water supply and sewerage for the rapidly expanding population centres. It was the Water Resources Act of 1963 that consolidated water resources management at a regional and national level, creating River Authorities responsible for enforcing the law in relation to water resources. The 1963 Act set the legal basis for regulation of abstractions and impoundment of water.