By the early 20th century, so much water was being diverted off the San Joaquin River and its tributaries that the river was no longer suitable for navigational purposes. As a result, commercial navigation began a decline starting in the late 19th century and was completely gone by 1911. With over under irrigation along the river by 1900 – this figure has only grown hugely since then – the river and its tributaries became much narrower, siltier and shallower, with large consequences for the natural environment, for sustainability of water supplies in its valley, and also huge changes for water politics in the state. The San Joaquin and its tributaries seemed to give rise to just about every single possible argument over water, including such cases as "When is a river not a river?" referring to the difference between a slough and a marsh. It has been said that fights over the river have caused "some of the most bitter and longest running lawsuits ever to clog the courts. Arguably, it is the most litigated river in America."