# New design - help with conceptual design ?



## corneliani (Apr 2, 2019)

I've come to terms that TTTF in Atlanta isn't going to work w/o an irrigation system. I see this forum seems to have some knowledgeable folks when it comes to this stuff... any chance I can get some preliminary feedback on how best to approach the design? I want to keep it as simple as possible while still doing a satisfactory job.

Here's a quick overview of what I'm needing to water. The orientation of the pic is exactly North (house is facing E/NE) so I get full sun on the driveway side (where my 70' anno is) and morning & evening shade between the house and the mulched area (compliments of a couple large maple trees). Utilities & county easements are at the street, not sure how/if I'd want to cross into that area. There are 2 landscape beds at the corner of the lawn/driveway area - i'm ok with hitting these with the lawn sprinklers as the pots w/annuals can be hand watered if needed (that's mommy & the little ones job anyhow  )



TOPOGRAPHY LINES (approx 10' drop along the 100' portion of street ROW)


CURRENT STATE OF LAWN, HAVING GIVEN UP ON IT SINCE LOSING IT IN JULY


APPROX LOCATION OF MAIN WATER LINE, FROM METER @ STREET TO WHERE IT ENTERS HOUSE


Sooo.. with all this info.... do I simplify this and treat it like one big square, watering over the 1000 sqft of mulched area? Or is there a way to water smartly without putting in 100 heads.

EDIT: I haven't calculated the GPM yet but I know I was pushing 100psi when I was building the house. It's on a 3/4" meter, and I think the pipe is 1" Poly. (i know i know) lol
Also, due to not having Curb & Gutters in our subdivision we get lots of water runoff coming off the street. I can sacrifice efficient coverage in the front due to the deluge of water that makes up for it when it rains.


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## hsvtoolfool (Jul 23, 2018)

You'll certainly need to dial down that PSI. The GPM you measure will determine if big rotors are feasible. Given your pressure, it's a good sign you'll have plenty of flow. Have you read Mr Stryker's tutorials? Highly recommended reading even if you hire a contractor to judge who knows their stuff and who's a con-artist. If you DIY, then follow his rules and you'll be fine. It can be intimidating at first,

I'd probably use big Hunter rotors in the large area, and MP Rotators in the small areas. Tough to mix and match types and get even precipitation rates though. I'd personally rather have lots of heads with minimal water use than the shotgun approach that many installers do. But that's just me.


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## corneliani (Apr 2, 2019)

I just did a search for Stryker and if it's the irrigationtutorial website, yes, i've referenced it (haven't read it end to end) but recently I've been having issues accessing the content. I just came across a link in this forum for an archive so I'll see if that works better.

I will attempt to DIY but being a contractor it's not something i'm afraid of. Plus spending $2-3k for one weekend's worth of work makes me cringe - albeit I usually regret these decisions afterwards but going into them I'm all in :| .


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## hsvtoolfool (Jul 23, 2018)

I DIY'd my front yard using Mr Stryker's web site. My front lawn was small with several small, curvy areas and a typical sidewalk street strip. So the decision to use MP Rotators and drip irrigation in the mulch beds was easy. The result was great thanks to Mr Stryker's knowledge and advice, but that's the extent of my experience as an irrigation designer and installer.

Selecting heads for middle-size areas is a tougher choice nowadays. My back yard is 10K and closer to your present project size. If I wanted to keep this a 100' x 100' open lawn, then I'd go with Hunter I-20 rotors. Since I'm planning a large paver patio, 12 x 16 garden shed, and several large mulch beds, the resulting lawn will probably be small enough that MP Rotators will again be an obvious choice for me.

Your large 75' x 70' area would be an easy choice for rotors if the large tree and mulch area wasn't there. I honestly don't know what to suggest. Personally, I would use MP Rotators due to the complex shape. The initial investment might be more work and expense compared to rotors, but the water use is lower in the long run. Then again, the cost and work difference may not be significant.

Assuming your GPM at the curb can support rotors, I think you'll have to run the numbers both ways to decide. Do one design with an assumed rotor-to-rotor distance that's reasonable. Rotors can throw as your flow rates support. Then do a second design with an assumed 20 to 25 foot head-to-head MP Rotator distance. While there are MP Rotators spec'd at 30 and 35 feet, I strongly recommend keeping the maximum distance for MPs around 25 feet and overlap the sprays by a foot or two. My experience with MPs is that the multiple, tiny streams are much more fragile than a rotor's big single stream. They're awesome below 25 feet, but a light breeze strongly affects them at longer distances.

The small side areas are easy choice for MP Rotators. I habitually mention Hunter products because that's my preference, but I'm sure the equivalent Rainbird products are fine too.


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## corneliani (Apr 2, 2019)

Ok. I've managed to work my way through the irrigation tutorial and know more about fluid dynamics than I ever thought I would! I've laid out my design using the MP rotators, as @hsvtoolfool recommended. It was actually an easy choice once my sloping yard & smaller areas were considered - not to mention the clay soil that won't perc too quickly. So now I'm left wondering if my spacing/layout is acceptable.

A lingering question I have: what is the real world radius for the MP Rotator relative to the spec sheet? For ex, MP2000/180 @ 40psi shows a range of 19'. Should I space it at 18'? 16'?? I tried to space them at 16' but some areas are 19-20'.. the next step is is the mp3000 with a 30' range.

2nd question: is running the lateral & heads alongside the street & driveway a regrettable design??!! It sure is efficient doing it the way I laid it out.

Lastly: my water specs are crazy high. I tapped my water line near the meter & installed a temp spigot to verify the pressure & flow, and it's coming in at 105psi and 30 gal/min !! Talking to Hunter reps they said their pressure reducing heads will take me to the appropriate pressure but at that incoming PSI it may cause a short lifespan. Anyone have any opinions on the need for an inline pressure reducer? This project is getting expensive fast!

Here's my layout. I color coded the zone groups based on watering requirements (sunny areas that dried out quicker are in green, and shady areas are red).


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## g-man (Jun 15, 2017)

1) it is not 19. 19 will be in a perfect zero wind day with a perfect level head. 18 is close to reality for me.

2) I ran my laterals next to the driveway. If there is any crew doing any cable work (cable TV, fiber, telephone), it is less likely to be cut. If you have snowplows and a street, offset the heads from the street by 4in to prevent the heads from being ripped out.

3) at 108psi, you need a prv (pressure reducing valve). Irrigation tutorials explain it and why you need it. You might want to add one for the whole house. 60psi is ideal.

The layout needs work. You need opposing heads in the red and blue.


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## corneliani (Apr 2, 2019)

@g-man - Thanks for the feedback. I called Hunter tech support and they confirmed that ideal real-world layout would be 10-20% less than spec, dep on grade/wind/etc. (15-18' spacing)

I saw that lack of head-head coverage in the red zone. The shade + large tree roots in that area make me hesitant to trench for those heads and thus spaced the opposing mp2000 heads at 15-16' hoping for more overlap. I'll see how the trenching goes, I just may try to sneak in a head or two in there if no obstacles in the way. But the distribution uniformity graphs do show a steep drop off at the edges... may be worth it to make it happen. Thanks for bringing it up.


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## hsvtoolfool (Jul 23, 2018)

I agree with g-man 100% and your layout looks good...

* Install a Zurn Wilkins 1" pressure reducing valve in the main line from the meter and dial it down to about 50 PSI using a $10 pressure gauge...

www.amazon.com/Zurn-Wilkins-1-NR3XLDU-Pressure-Reducing/dp/B07BYFF9PN

www.sprinklerwarehouse.com/products/tools/pressure-gauges/aqualine-pg100s-3-4-pressure-gauge-0-100psi

For that matter, measure your house pressure while you're at it. You house should have a PRV installed somewhere and you need to check it now and again to be safe.

* I would go 16' max spacing with MP2000 due to real world conditions mentioned above (wind, slope, individual nozzle quirks, etc). You can always space in an extra head and dial them all back for perfect overlap with less wasted water. A few heads 18' to 19' apart that undershoot won't hurt anything but...

* Higher elevations and sod near hot asphalt (a.k.a. those darn dry areas!) should be spaced closer while low areas are less demanding and can be handle farther spacing. In the real world, zones seldom need the same amount of water. I run the "low zone" in my yard 10% less than the "high zone" and 30% less than my street strip. You know best what's dry and soggy. Keep that in mind with your zone layouts.

* Which area do you think will annoy you most if it's a little dry? How important is perfect coverage for that little area tucked into the upper-left corner? I'm not saying do this, but it's a design trick you might consider. For example, move that lone head in the upper-left corner to the center-front of the mulch bed facing the street. Then shift the remaining heads toward the driveway a bit. You may get better coverage at the front-center and near the driveway. Okay, now you have a tiny dry spot in the upper-left corner. So what if you modified the mulch bed to get rid of that dry spot? There's no rule that says you can't shape the mulch bed to match your sprinkler patterns.

* I kept all my heads a good 12" away from curbs and driveways to reduce the damage risk posed by bad drivers. The trade-off is that I must go a little past 180° on those heads and waste a little water on the driveway. So I don't have any dryness in the "blind spots" behind those head. But this trick is well worth the peace of mind since my neighbor's kid has put a tire track in my lawn several times over the past couple years. I got this idea after learning from my poor neighbor down the street who replaces a couple heads at the end of his driveway at least every couple years.


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