Landscape Management, November 2016

profit centers Deep rooted equation tify F inding the right balance between lowering a sites water usage and maintaining a large plant palette isnt a one and done job Gone are the days of the set it and forget it mindset when it comes to landscape water management especially with water for urban landscapes becoming more limited Instead take an active approach by using irrigation monitoring systems communicating with those walking the sites and establishing practices But how can you go deeper and actually refine your landscape irrigation method In an Oct 21 webinar with the Irrigation Association IA Refining the Landscape Watering Coefficients for Your Sites Mark Crookston irrigation management department manager for Northern Water in Berthoud Colo shared this equation to calculate soil water depletion see key for definitions so you can make appropriate adjustments to your watering strategy ET ETo x KvKdKs Ke x Kmc Here are the six components in the order of the equation of determining a landscapes evapotranspiration ET that you need to verify and refine so you can improve efficiency 1 RefeRence eT eTo Use the best available data source whether its from a nearby weather station on site air temperature sensor or the internet Just remember there is lag time between what happens and the response Crookston says The data are normally good when averaged during a five to seven day period If you rely on a local weather station make sure its in an open area over well watered vegetation thats away from buildings and pavement An on site air temperature sensor can include a sunlight sensor and smart irrigation controllers Figures you will find on the internet arent site specific they are typically an average for a large area 2 facToR foR VegeTaTion Type Kv Vegetation categories include trees shrubs ground cover annuals mixture trees shrubs and ground covers coolseason turfgrass and warm season turfgrass You can choose the Kv for high performance acceptable appearance or low maintenance depending on the clients expectations Trees for example are 090 to 095 for high performance 070 to 075 for acceptable performance and 045 to 050 for low maintenance See the IAs Irrigation Sixth Edition for all plant categories and performance levels 3 facToR foR planT DensiTy Kd Consider the collective leaf area of the plants covering or IrrIgatIon Water ManageMent How to identify and adjust key irrigation parameters for efficiency BY Lauren DoWDLe CIT IrrIgreen saves waTer The Center for Irrigation Technology CIT an independent tester and evaluator of irrigation equipment found IrriGreens Genius Irrigation System used 40 percent fewer gallons of water while increasing soil moisture by an amount equivalent to its competitors amerICa The beauTIful Rain Bird is participating in a renovation effort at the National Mall in Washington D C which experiences damage from 3000 permitted events and 33 million visitors each year Rain Bird products including the companys Smart Pump Rain Watch IC System with Stratus II control software and Smart Weather products have been integrated into the 18 acre restoration newsFeed LANDSCAPEMANAGEMENT NET NoveMBeR 2016 42 Mark Crookston photo istock com redmal