Since the 1960s dewatering, or removal of water from streams and rivers, has doubled and around 60% of the Earth’s runoff is captured (MEA 2005). The removal of freshwater from rivers and streams for anthropogenic use before it reaches the coast is having a negative impact on many coastal estuaries. Half of the world’s major cities are within 50 km of the coast, and coastal populations are 2.6 times denser than those further inland (Crossland et al., 2005). Technological advances in the collection of freshwater is continually improving, further straining available freshwater resources. Removal of freshwater is altering three kinds of environmental flows including instream flow, freshwater flow within rivers and streams, inflow, freshwater flow into estuaries from rivers, and outflow, water flow from a river or estuary into the sea (Palmer et al. 2008).