I would like comments on tweaking my existing irrigation system for capacity and pressure. I had a neighbor put in two well points for me and hired an irrigation company to install the system (lesson learned). I have ended up totally redoing the irrigation system due to landscaping and expansion of needed watering areas. I have left the pump and well alone, until now.

I have two well points (1 1/4" Brady) set 85" apart and down about 15 - 20 feet in good clean sand (A-3) that draw from the groundwater that flows down the sand ridge the property is on. The well points are located on the edge of the swamp/floodplain of our creek at the bottom of the ridge. The static water level is currently 3.5 feet below surface and will flucuate up to 1 foot during wet season. We are in the dry season now (St Augustine, FL). I do not know exactly how much well point is in the ground, since my neighbor installed them. I just remember getting the casing down about 15 - 20 feet using the "washing" method, dropping the well points down the casing and removing the casing.

The irrigation people were the ones to hook up the well points, pump, etc. I have a Myers HJ Series 1 HP shallow well jet pump with a Square-D pressure switch and a 1-gallon tank. The intake line has a check valve and union. The outflow line has a Watts series 7 dual check valve, hose bib, gate valve, and a clean-out filter (I think) before connecting to the valves.

When the system was connected, the irrigation people said I was getting 15 gpm for the system. That was about 2 years ago. Since the redesign, I have notice the system effeciency has dropped. Today I tested the system again and yielded the following results:

5-gallon bucket test from garden hose connected to the hose bib coming out of the pump yields an average flow of 11.3 gpm.

The pressure readings with the garden hose were:

Cut-In = 30 psi, Running = 41 psi, Cut-Off = 54 psi

Turning on the irrigation system and running a zone yielded the following pressure readings:

Cut-In = 30 psi, Running = 50 psi, Cut-Off = 54 psi

I have 13 zones with a maximum elevation difference of 10.5 feet. The dynamic water depth is about 5 feet right now. I am using Hunter PGP rotors and Rainbird sprayers. The main lines are 1" and the laterals are 3/4".

The redesign was talored around 10 gpm based on the flow at that time. The system operates OK but could use some more flow. I have to blow out the sand build up from time-to-time to keep the flow what it is now. I would like to add some rotors to fill in some areas of dryness and provide overlapping for more efficient watering, but I am maxed out on zones and do not have the flow to add to existing.

Are the pressure switch setting OK or do they need adjusted?

Is the pump adequate for what I require?

Do I need to add and/or replace the well points?

How can I increase the flow (15 - 20 gpm) and maintain pressure for the rotors?