Tuesday, November 22, 2011

New WUEP research sites online! – Part 2 of 2

This is the second part of the report back detailing the final Landscape Irrigation Project research sites initiated this summer. A summary of the summer’s efforts follows the site descriptions.

Coral Gables (South)

When the UCU assessed this homeowner property in early summer for the irrigation rebate program, I made a solemn vow to move mountains to convince the owner to participate in the research. Why? In short, it is the research equivalent of prĂȘt-a-porter – two zone digital irrigation system on city water! Further, the digital timer on the property is the same brand/model as the smart timer under study, so the retrofit would simply involve switching face plates and mounting the on-site weather station!

In September when the owner finally agreed, we moved on retrofitting the system. The only caveat was that, unlike any of the other properties recruited this summer, the owner chose the soil water sensor (SWS) technology over the weather-based timer!

The add-on sensor we installed is a two component sensor with one part connected to the controller and the other part wired to a valve in the field. Because valve location was not readily obvious during the initial assessment, we brought along a valve finder.

The valve finder is a two-piece apparatus. One part connects to a ground and the zone wire of the valve one is trying to locate; the second part is a wand with headphones that tracks power in the valve wire and emits a noise which grows louder as the valve location gets closer.

The equipment worked like a charm for us and once both valves were located the water meter installation began.

Unlike the evapo-transpiration (ET) study sites, SWS study sites require installation of two water meters, one for each of two zones. One zone is set to by-pass and always waters on schedule; the other zone is controlled by the sensor.

On our second visit, we focused on improving coverage and eliminating excessive heads. The following images illustrate some of this work.

Sprays in a shaded pathway cause swamp after every event: removed!

Ridiculous spray location? More like redunkulous! Removed!

Spray head in a rotor zone: Removed!

A rotor is added to a corner to improve coverage

Coral Gables (North)

Much like the above property, as soon as I stepped onto this property for the rebate program irrigation assessment in mid-summer, I knew it was research-worthy: a five zone digital irrigation on city water.

The only catch here was that the owner had to choose the weather-based timer or all would be lost!

Why? Because there is not an inch of turf grass on this property! It’s all low-maintenance, drought tolerant shrubs and established trees, not the ideal landscape for SWS technology. In addition, the timer is located in a perfect area on the property for mounting the on-site weather station above all possible obstructions.

By August we were working on retrofitting the irrigation system for research. Our first visit was limited to exchanging the existing digital timer for the weather-based timer and installing the weather station.

The most daunting task during the install involved scaling the 20ft garage structure to mount the weather station while racing a looming thunderstorm to the finish-line. We succeeded on both counts.

Supplies are gathered in a bucket tied to wiring

The bucket is lifted up to the roof

Weather station installation begins

All finished...with a storm on our heels!

During our second visit we completed site preparation.

We installed a backflow device to safeguard the potable water lines (despite having irrigation tied to their water main, many South Florida properties do not include this detail).

We added the water meter on the system mainline to track water-use. We also did some redesign work to improve the application rate on several of the five zones.

Smart = no mess, no fuss!

My initial suspicion about this property was correct. For a homeowner with a low-maintenance landscape but firmly committed to maintaining the irrigation system on year-round, the weather-based timer could not be more ideal. Programmed as accurately as possible (shade factor, plant type, plant density, etc.) the weather-based timer has calculated that since September, when this site went online, persistent rain is adequately replenishing moisture in the landscape and it has not allowed any irrigation events to date. 100% savings!

Summer’s summary

Eleven research sites were initiated in the summer of 2011. Of these sites, ten are ET and one is SWS. With respect to retrofitting, six sites were complete retrofits (mechanical/indexing to digital/valves) and five were partial retrofits (digital to smart/SWS). Adding these totals to the 2010 research sites (11) that elected to continue another year in the study, the active research site total is 22.

See Part 1 of 2 here.

Monday, November 14, 2011

NRCS video on particle-size analysis by hydrometer

This is a video from USDA - Natural Resources Conservation Service that explains how to perform particle-size analysis using the standard hydrometer method.

The video highlights the important steps and precautions (e.g., constant temperature and proper plugging) that need to be taken to ensure accurate hydrometer readings.

The video also addresses the limitation of this method when the sample to be analyzed is high in soluble solids (i.e., flocculation occurs and particles settle unnaturally). In these cases readings from the hydrometer will not be accurate and another method that removes soluble solids is recommended.

See the video here.