© Office of Water Programs — 2010 The Office of Water Programs Christian Carleton, P.H., CPSWQ, CPESC Brian Currier, P.E. David Alderete LID Implementation Challenges: Monitoring and Measuring Results Select OWP Experiences

© Field monitoring guidance Results of testing at Sacramento State

Field Monitoring Guidance Flow Monitoring Issues –Accurate rain gauges and drainage areas –Influent flume sizing We know large storms bypass, so why size flumes to monitor what we already know? Size flumes up to the design storm for water quality purposes 0.16 in/hr is a common water quality design intensity, so 0.5 in/hr may be reasonable for a good range of storms. –Effluent flume sizing Smaller flumes should be used for flows from filter media or orifice- controlled outlets

Do not ignore small events –Monitor flow on the small events and consider a few water quality events as bonus data –There is far more uncertainty in the hydraulic performance than there is in the quality of filtered water, so focus on the flow! Small storms are avoided to minimize ‘false-starts’ for water quality samples due to insufficient volume to collect a minimum number of aliquots. Field Monitoring Guidance

80/20 Sand/Compost Initial hydraulic capacity can be very high and depends on drying Maximum was nearly 500 in/hr Mostly-saturated hydraulic capacity ranged from 40 to 60 in/hr, though as low as 17 in/hr was observed. Results of Testing at Sacramento State

Dry-weather flow negatively impact LID systems –Soil doesn’t have a chance to dry out –How does it happen: Raised-landscaping runoff Irrigation overspray Vehicle/street/sidewalk/driveway washing Results of Testing at Sacramento State

Treatment is governed by hydraulics Instantaneous and short-term treatment tests are very misleading Filtered vs. bypass depends on: –Media type, depth, area, and ponding depth –Local hydrology –Catchment size and shape Results of Testing at Sacramento State