Paul Whitehouse travels across the country to explore why waterways are in decline.

Paul continues his journey, travelling to Wales and the south of England. Visiting the River Wye, he sees how explosions of algae, caused by fertilizer runoff from farming, are part of a cocktail overwhelming the habitat. He travels to Hampshire where he hears about the damage being caused to our rare and precious chalk streams, before discovering how regular sewage discharges on the coast are causing problems for Whitstable's famous oyster industry.