Fertilization of oligotrophic streams by the addition of inorganic nutrients is under investigation as a technique for fish habitat restoration and mitigation. Automated methods using liquid agricultural fertilizers were introduced in British Columbia by the Ministry of
Environment, Lands and Parks to improve efficiency in adjusting inputs to changing flows in larger streams. Target rates of nutrient addition were previously maintained by periodic manual adjustments to gravity flow from tanks secured at the stream bank. An automated liquid fertilizer metering system was developed to provide a more effective and reliable delivery of nutrients. A system employing a water surface detector and pump was field tested in 1995. A gravity fed injector system, pre-programmed to deliver nutrients following a simple exponential recession matched to summer flow hydrographs was field tested in 1996. The pre-programmed system proved easier to install and simpler to operate that the flow proportional pump injector.
Modifications to improve performance and reliability of the microprocessor and motor drive circuits of the 1996 prototype are underway, and the modified system will be field tested in 1997...
Larkin, G.A., Ward, P.R.B.; Ashley, K.I.; Slaney, P.A.; Koning, C.W.; Mouldey, S.E.. 1997. Recent Advances in Liquid Fertilizer Injection Technology for Stream and River Restoration. Ministry of Environment, Lands and Parks; Ministry of Forests. Watershed Restoration Project Report. WRPR05
Topic: Watershed Restoration Program
Keywords: fertilizer, restoration, oligotrophic
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