Annual Precipitation Trends Upwards for Pennsylvania

Below is a good article from the Extension Office at Penn State.  It discusses an increase in annual heavy precipitation events, resulting in the state become more drought "tolerant."

http://extension.psu.edu/natural-resources/water/news/2014/penn-state-webinar-asks-2013-is-pennsylvania-becoming-drought-resistant#.VGNsnanJhKs.twitter

Does this mean we no longer need to irrigate our lawns in PA?  Absolutely not.  Our most recent summers have include extended periods of no or little rain.  The lawns have needed supplemental water to prevent dormancy.  Once dormancy starts, a lot of water is need to bring the lawn out of dormancy.  Also, when lawns become stressed, this is also the time weeds start popping up.  The amount of fertilizers and pesticides required can be reduced with a healthy lawn.

Does this mean we do not have to minimize the amount of water we put on our lawns?  Again, absolutely not!  Water conservation is important.  But, if you do not feel strongly about water conservation, over watering your lawn is still a bad idea.  It promotes shallow root development and disease problems.  Just like people, too much of a good thing is also bad for grass.

Product Substitutions and Non-Proprietary Plans

Found in the Quality Assurance section of our specifications we include the following:

"Random product substitutions will not be accepted.  The functionality of the irrigation design and system is based on characteristics of the products listed in these specifications and accompanied plan.  Contractors wishing to substitute any product must submit, in writing, reasons for proposed substitution, product specifications, revised plan, and performance data to the Owner’s Representative and Irrigation Consultant.  If written approval is granted, products may be substituted.  Any products found during the final walk through, not previously approved, will be removed and replaced with an acceptable product at the contractor’s expense."

Similar products can have varying hydraulic characteristics from different manufacturers.  Different flow rates, pressure requirements, and operating ranges.  To minimize sizes due to pressure and flow requirements, a designer has to choose one product to make accurate hydraulic calculations.  Changing products on a plan can require changes in other products, pipe sizing, scheduling, or water requirements.

A non-proprietary plan is almost an open ended plan allowing the contractor to select the products. The products selected must meet the minimum specifications, but can still have varying hydraulic characteristics.  When designing a system, that a specific product is not called out, we need to design for the worse case.  This can lead to higher pressure requirements, larger pipe sizes, larger valve sizes, etc.

The biggest selling point for non-proprietary plans is to avoid a manufacturer having the ability to charge more for their products.  However, contractors typically buy irrigation products from an irrigation distributor.  The manufacturer has no control of pricing per project, the distributor does.  Most distributors carry multiple products from multiple manufacturers.  A contractor has the choice to purchase the materials for each job from two or more local suppliers.  This results in distributors trying to undercut the other for the sale.  Usually on the same product.

When bidding from a plan, the biggest irrigation cost variable is labor.  Most products, of similar quality, are close in price.  Usually the savings is minimal when opting for one manufacturer over another.

Too Many Heads / Sprinklers!

Looks like there are a lot of heads!  Maybe too many?

Looks like there is a lot going on, any way we can clean it up?

These are the most common responses received, the first time an irrigation plan is reviewed.  Irrigation plans are much more functional than visually appealing. 

Distribution uniformity describes how even the water is being applied throughout an irrigation zone.  If we place measuring cups in different locations, we want close to the same measurements of water.  

One aspect of irrigation design, that affects distribution uniformity, is head spacing.  A designer uses personal experience, manufacturerer's data, and site condtions to decide on the best head spacing.  Approriately spaced heads results in a higher distribution uniformity.  Heads spaced too far apart results in a lower distribution uniformity.

A low distibution uniformity rate results in a mix of over and under watered areas.  A high distibution uniformity rate results in minimizing water use and maximizing plant health.  Yes it is true that water in our area is viewed as being cheap, but replacing plants is not.

Working with an Irrigation Consultant: How to Get Started

I was recently told that many engineers and landscape architects are not sure how to work with an irrigation consultant.  Below are the best instructions to get started:

• Email us details about your project and include questions and concerns you may have.
• Call us.

Yes this seems overly simple, and we try to make it that way.  You have enough to worry about with your project.  We also understand that you may not have a strong background in irrigation.  That is OK.  That is why our company exists.

Irrigation Construction Inspections and Final Punch Lists: Don't Worry, I Saw the Sprinklers Work

A couple of months ago I followed up on a project we completed specifications and a design for.  The contractor was currently installing the system.  I asked if they would like us to complete a couple inspections during construction.  The service was declined, and I was notified that the general contractor (GC) had it under control.

A week ago I received a request for a final walk though.  The GC had already approved the system, but the owner wanted a second opinion.  Most of the irrigation system was below ground at this point, but I was able to perform a visual inspection of the exposed components and view the system in operation.  The following is a partial list of the items out of compliance with the design and specifications:

1. Valve boxes were partially above grade creating a tripping hazard and becoming more susceptible to damage from mowers.
2. Sprinklers nozzles were not as specified.  An additional 900 gallons of water per day of operation is applied to the turf area than required.
3. Two major pipe breaks were found.  The system was designed to operate at 35 gallons per minute.  Exact amount of water wasted could not be determined.  Surrounding landscape and plant material will be damaged if not corrected.   
4. One zone contained different types of sprinklers.  A portion of the landscape covered by this zone would be over/under watered.  Possible loss of plant material.

These are just 4 out of the 21 items listed on the completed punch list.  Most of the additional items relate to the reliability of the system.  Inferior componets were used in lieu of products specified.

So how was this system signed off on and approved prior to this walk through?  Because the GC saw sprinklers throwing water.

What Brand Should I Use?

Early in the irrigation design process, brands and models of irrigation components are selected.  Sometimes this is dictated by the owner of the site.  Other times I am asked for recommendations.  There are some products that are unique to a manufacturer.  There are also a lot of similar products that all manufacturers offer.  So how do I choose?  Below is just a brief list of considerations before I recommend a specific product:

• Price:  Let us get this out of the way first.  It is the first thing that most bring up.  While I do not think this should be "the" deciding factor, it is a factor.  If there are two or three products that get the job done, and are reliable, I usually go with the lower priced item.
• Location of the project / Product availability:  There is a lot of disparity between the number of irrigation distributors in New Jersey vs. Harrisburg, PA vs. Washington D.C.  Some products available off the shelf in D.C. may need to be special ordered in Harrisburg.  When possible, I try to stick with what is locally available.
• Local contractor experience:  Contractors' experiences with certain irrigation technologies can vary greatly in our area.  This is not a slight to any contractor.  The differences in level of experience can be a result of many factors.  Maybe a locally based sales rep pushed it hard in an area, or the product was more practical for local projects.  A prime example of this is when two-wire was first introduced.  It was very popular along the beaches in Maryland and Delaware.  It provided a wonderful solution to the phased in construction associated with many of the large development projects, and was quickly adopted.  There was little benefit and cost savings to be had on the smaller irrigation projects in Central Pennsylvania.  The result was a slower adoption rate for many local contractors. 
• Product performance / Site conditions:  Every site has unique conditions.  Some products are a better fit based on their specifications and/or performance.  
• Reliability
• Local support:  Some people manufacturer's have in the fields are better than others.  If they have a track record of being unresponsive it is usually best to steer clear of their products.  No manufacturer is immune to occasional manufacturing problems.  Having good people in the field helps correct these problems quickly with minimized issues to the end user.
• Past product experience:  From 1998 to now I have used many products on numerous projects.  Many good ones, and some I have learned to avoid.

So how do you select which products to use?

Conserving Collected Stormwater

It has become more common in our area to use an irrigation system as a way to dispose of collected stormwater.  On paper this sounds like a very environmentally friendly solution.  However, many engineers and architects are failing to see the the full potential of installing an irrigation system.  Their narratives discuss disposal of the water and dosage information.  One could easily confuse their irrigation narratives with that of an on-site septic system.  It is very clear that their goal is to get rid of the water as soon as possible.  However, is this sustainable?  If we install solar panels, and we have multiple sunny days, should we turn on all the lights to get rid of our abundance of collected electricity?

On a recent project, we were able to irrigate most of the site, with only collected stormwater.  The irrigation system is programmed to operate above the plant material ET rates and below maximum soil loading rates.  The basin will be completely drained once a year by the irrigation system.  We estimate this to occur in October.  If the quick disposal method were followed, we would irrigate at the maximum soil loading rate.  We estimated that we would run out of water 4 months of the year, probably resulting in some brown turf.

Which way do you feel is more sustainable and looks holistically at site design?