Bedfordshire current England english flow Great Britain green natural nature oxygenate oxygenation river summer trees water weir architecture cascade dam fall fresh historical old oxygenated power stone strength strong tunnel turbine wales wall welsh banks course great Ouse reflections waterweed bridge force freshness habitat moss plants wild woodland air amount anasthesia gas anesthesia controller flowmeter gage gas gauge hospital illness instrument laughing gas medical medical equipment messure nitrous oxide operation oxygen oxygene regulater rotameter scale sleep tool volumeter work Asia farm field healthy plant purple anchored buoy data-collecting-buoy dissolved-oxygen electronic-data-transfer estuarine estuary fish-kill-mitigation floating-device fresh-water improving-understanding monitoring-buoys moored oxygen-levels salinity salt-water scientific-advisory solar-panel solar-powered stationary tidal tide water-quality water-quality-management autumn color forest hill life mountain orange red rusty three threes yellow