Weirs – Planning, Building, And Measuring Flows

Tomorrow is Christmas 2015!  Merry Christmas all.

Weirs are the least expensive permanent measurement device you can install.  Materials will cost the diverter in the range of $300 to $2,000; hiring the backhoe to set it in place probably costs more than the materials, unless the diverter already has a backhoe or crane.

The weir below was precast by Briggs Manufacturing in Willows.  The weir is a cast concrete, 3-sided box with board slots for 2″ lumber.  It’s pretty simple, and relatively easy to install.  This particular weirWeir_Showing_Board_Slotsneeded metal wing-walls to keep the dirt on the sides from washing out.  Note that there are two board slots on each side, one for the boards to slide in, and the other to help make sure a nappe or air gap is created as water flows over the boards.

Step one is determining if there is enough fall in head from upstream to downstream.  A weir needs 0.7 feet (0.7′), or 8.4 inches (8.4″) of fall to be sure it will work correctly.  The 0.7′ figure is because the pool of water needs to be a maximum of 0.45′ above the top of the weir boards on the  upstream side.  Then, the water in the ditch downstream of the weir needs to be at least 0.25′ below the top of the boards so the water flows freely, separating from the boards and having an air gap on the downstream side.  0.45′ + 0.25′ = 0.70′.Sticking_Weir_sharpened

The photo above shows a ruler in tenths of a foot, held vertically on top of the weir boards.  This is called “sticking the weir”.  When the ruler is turned face-on to the flow, the water will climb up to the same level as the flat pool upstream of the boards.  It’s physics – standing water has an energy level equal to the height of the water surface.  Moving water has both potential and kinetic energy, so the energy level or line is above the surface of the

Sticking_Weir_zoom_sharpenedwater.  Moving water stalls behind the face of the ruler, giving the height of the water if it were standing still.  That is the water depth that has to be measured for weirs.  The photo is showing a water level of 0.31′ – it wobbles up and down just a little – so we know this weir is flowing at about 0.6 cfs per foot of width.

If the ditch is very flat and shows no ripples when flowing, it’s probably too flat, and an orifice or a flume will be needed instead of a weir.  Future posts will discuss those measurement devices, and others too.

Step 2 is figuring out how big a box is needed.  Fortunately, there is an easy rule.  1.0′ feet of width is needed for every cubic foot per second (cfs) that will be diverted.  For example, if the diversion will be a maximum of 3 cfs, then the diverter will need a 3′ wide weir.contracted_weir  If in doubt, get the next larger size since the cost is not much more.  The reason for this rule is that a weir can be accurate to plus or minus 5%, well within the accuracy needed for diversions in the field.  If the pool upstream of the weir boards is more than 0.45′ over the top of the boards (or less than about 0.1′ over the top of the boards), the accuracy of the weir is worse than the standard.

Measurement devices need to be planned and operated correctly to assure the diverter (and ditch-tender, and neighbors, and the State Water Resources Control Board, andsuppressed_weirpossibly 10 other state and federal agencies, and possibly even the Superior Court in the very worst case) that the flow measurement is correct.  It’s like a truck speedometer – they can get less accurate over time.  It’s no problem if they read faster than the driver is actually driving, but if they read slower, the driver is in danger of unknowingly speeding and getting a ticket.  Ouch.

The actual installation process is fairly simple to describe.  Get 1 to 4 yards of 3/4″ minus road base rock delivered on site, trucked from the gravel plant.  To save a lot of hassle, skip the forming up and pouring a concrete weir, and just call Briggs Manufacturing and order a weir to be delivered on site.  Dig a shallow, level (flat), square hole in the bottom of the ditch, about 8″ deep, and 1′ longer and wider than the bottom of the weir.  Shovel base rock into the hole about 2″ deep, and compact it.  Rent a gas-powered thumper, or use the bucket of the backhoe.  Pour another 2″ and compact it.  Use a level and make sure the top of the base rock is level side to side, and along the ditch.  Since it packed down during compacting, add the last 1″ and compact it, so the top of the road base is about 4″ below the bottom of the ditch upstream and downstream.

The installer needs to make sure to have a piece of 1″ steel bar that is about 1′ longer than the the width of the weir box.  There is one hole through the top of each side of the weir – stick the rod through that and hook onto it with a chain to lift the weir.  Set it in place, and make sure it is sitting level.  The installer might have to gently press down on one side with the backhoe to get it completely level.  Now the floor of the weir will be at the level of the bottom of the ditch.  Remove the steel bar, and fill the weir box inside about 2′ deep with some dirt.

Next, install the wing-walls, if needed.  These will keep the material on the outsides of the weir from washing out in a steeper ditch.  Then backfill with the remaining road base on the sides, compacting it for each 6″ of depth.  If tNew_Weirhe native soil holds water well, it could be used instead of base rock to backfill, saving a little bit of money.  Remember the dirt that was placed 2′ deep inside the weir?  This will keep the weir weighted down so it does not move during backfilling.  Also, it will keep the sides from being slightly bent in by the pressure of compacting the backfill.  The reinforced concrete weir boxes are strong but the walls can be bent in with enough force.

That’s it!  The weir box is installed and ready to go.  New weir boards, usually 2″ x 6″ or 2″ x 8″, should be cut about 1″ shorter than the width inside the board slots.  For example, a 3′-wide weir will have board slots about 2″ deep.  The full width from inside of board slot, to inside of the opposite board slot, is 3′-4″.  The boards should be cut about 3′-3″ long.  That way, when they swell a little bit, they won’t get impossibly stuck.

Happy measuring!  Good night to all, Merry Christmas, and blessings in the New Year.

How to Divide Up a Decreed Water Right – Part 2

…continued from yesterday’s Part 1….  To recap, in 2005, San Bernardinoans Arnold and Eileen Williamson bought property near South Cow Creek up in Northern California to retire on and build a new house.  They were set on drilling a new well and uncertainties in how much they could pump got them looking into their surface water right – do they have one for sure, and how much water is it?  They ended up taking their questions to an engineer who could answer their questions.  The map below is one of several from the report they got from the engineer, showing their property boundary on the 1965 decree map of irrigated lands:Ex_2_Williamson_Parcel_Outline_on_DecreeMap_reduced

The report cost $350.  They’re pretty sure they would have paid a lot more than that to see an attorney.  The engineer warns them that if it gets contentious and they can’t work out access to the water with their neighbors, they may end up having to get legal help.  He recommends Jeff Swanson if it comes to that – he’s an expert water rights laywer in Redding.  For now, though, they have documentation they can discuss with their neighbors to work on getting their water right to their property.

Their property is on land that back in 1968 belonged to Howard and Gladys Leggett.  It has an adjudicated second priority water right for irrigation equal to 0.063 cubic feet per second, or 28.5 gallons per minute, 24 hours a day, 7 days a week, from March through October.   This 2nd priority right is less than the second and third priorities on the upper creek and tributaries, but it is the highest irrigation priority on the lower creek.  Back when the property was flooded, that was usually enough to flood irrigate their entire lot to grow pasture or hay.  That’s great news!

As natural flows drop during the summer that amount is reduced and everyone with a lower creek second priority has to reduce their diversion by the same percentage.  In normal and wet years they could keep their pasture, hay, or whatever else they plant, irrigated for most or all of the irrigation season.  And whether or not they use the water, the right does stay with the land and protect their property value.

What else was in their report?  There was a cover letter, and next some excerpts from the decree.  Schedule 1 lists the places of use for all the original owners.  The Leggetts’ description takes up most of page 60; the Williamson’s property is on the 69.8 acres listed in the second paragraph for the Leggett land:

SCow_Sched1_Leggett_Places_Of_Use

 

Schedule 2 lists all the points of diversion, whether gravity diversions or pumps.  The Leggett property actually could get water from two diversions, a pump from the creek, and a proposed second, movable diversion on the creek.  That’s convenient – per the decree they could already divert their water from someone else’s existing diversion, or pump their water from Diversion 95, or they could get it from anywhere they can get agreement from the landowner!SCow_Sched2_Leggett_Points_Of_Diversion

SCow_Sched2_Leggett_Points_Of_Diversion_2

Schedule 6 lists the water rights for Lower Cow Creek – other schedules have rights for the upper creek and tributaries.  This is interesting: there are four priorities of rights and

SCow_Sched6_LowerSCC_Leggett_Allots_second_page

this part of the Leggetts’ property has a 1st and a 2nd priority right.  What does that mean exactly?  The decree explains that 1st priority rights are domestic – houses and gardens.  It’s a very small right and it is not clear whether or how it should be divided up among the all the subdivided parcels that used to be the Leggett ranch.  The engineer noted it in the cover letter.

How was the water right calculated for the Williamsons?  Using a geographic information system, or GIS, the engineer used his training and years of experience to precisely overlay the Assessor Parcel Map on the decree map.  Then he measured the acreage for both, and prorated the water right by area.  The following screenshots of the Excel spreadsheet shows these calculations.

TractMgmtSheet_20151222_Arial_12_01_reduced

TractMgmtSheet_20151222_Arial_12_02_reduced

TractMgmtSheet_20151222_Arial_12_03_reduced

Time to fess up: this was a water right subdivision of a made up parcel of land, and the Williamsons don’t actually own it.  However, this story is one that happens every day, when a landowner asks “How much is my water right, really?”  Having information before arguing with neighbors, seeing attorneys, sending legal letters, and going to court, can help smart people who generally have good relationships work out happy and agreeable solutions.  The Williamsons were smart and talked politely with their neighbors, the Turings and Poulens and Winters’s.  Now they have a good basis to live peacefully in their neighborhood for many years, and Arnold can borrow Charlie’s lawnmower until he gets his own.

Ex_2_Williamson_Parcel_Outline_on_Aerial_reduced

How to Divide Up a Decreed Water Right – Part 1

Back in 2005, Arnold and Eileen Williamson bought property near South Cow Creek in Shasta County.  They live in San Bernardino and plan to retire early, and build a new house on their land.  The parcel is part of an old ranch just off Highway 44.

The Williamsons paid $220,000 for the 3.55 acre lot.  That seemed high compared to similar parcels in the area, but they were assured the land has adjudicated water rights from South Cow Creek.

Arnold and Eileen brought their travel trailer to live on the land while they are building a new house.  Their savings account is in good shape so they are going to build a nice 2,200 square foot, single story ranch house with a garage and a shop.  They talked to a well driller 10 years ago and he assured them it would be easy to put in a well, for a cost of around $18,000.Williamson_Overview

When Arnold and Eileen went to get a permit to drill a well, they ran into unexpected problems.  Parcels on either side have their septic systems close to the common property lines, so their possible well locations are few.  Maybe a bigger issue is the passage of the Sustainable Groundwater Management Act in 2014.  Will their pumping rate be limited, and will their well-drilling permit application get held up?

Now the Williamsons are checking into their surface water right.  Is it enough for some pasture for horses and a few cows, in addition to the house and garden?  The Turings who live on the east side say there are no water rights.  The Poulans, to the west, say they have lived here for 6 years and they have never had water – they think the water right was bought off the place, or lost because of non-use.Williamsons_and_neighborsNow the Williamsons are upset and headed toward just plain mad.  The real estate agent said they had rights, and didn’t the title companies insure it??  After a few frantic calls, they found out that title companies don’t insure water rights.  But, their realtor gave them the number of some folks over on the north side of the highway, and they have a “decree map”.  Arnold and Eileen head over to the Winters’ place to look over the maps.  Brad and Jenny Winters even have the Internet address where the decree can be downloaded:  http://www.waterboards.ca.gov/waterrights/board_decisions/adopted_orders/judgments/docs/cowcreek_jd.pdfSCow_Sheet_5_screenshot

It turns out that the Cow Creek adjudication does not have maps, but an engineering report done a few years before the decree was issued does have the maps.  Brad and Jenny have that report, too, so they have Sheets 1 through 5 showing the “Diversions And Irrigated Lands” on Cow Creek.  Sheet 5 covers the area including the Winters and Williamson places.  Sheet 5 has a lot of “irrigated lands”Leggett_Focus_Area according to the legend – the green areas.

By looking at the maps, and their Assessor Parcel Map they have in their escrow package, it sure looks like their property is completely within the green area.  Great!  Now, how do they figure out if they actually have a water right?
AP_Map_59-98_croppedAfter asking around, Arnold and Eileen figure out they will need to see an attorney.  They call around and find out there are a couple of engineering companies that can see them faster, and they might cost less.  An appointment with Rights To Water EngineeringEx_2_Williamson_Parcel_Outline_on_DecreeMap_reduced   the next morning is their next step.  Within a couple of days, they have a nice report in their hands and answers to their questions.  So what did they find out?  That is an answer for the next post.

For now, good night to all….

 

Quick Change of Subjects: What’s a Water Right Permit Cost?

What does it cost to get a surface water right?  If your land is not riparian to the stream where the water is, or maybe one parcel is but your other 5 parcels are not, then you’ll need to file for a (Post-1914) appropriative right with the State Water Resources Control Board.

AlmondOrchard

Let’s say you want to irrigate 50 acres of new almond orchard in the Sacramento Valley.  How much water do you need for micros-sprinkler irrigation?  Let’s use the value for a 5-year-old orchard, about 3.33 acre-feet (AF) per year for irrigation and frost protection.  That number comes from the U.C. Davis Report Sample Costs To Establish An Orchard And Produce Almonds Sacramento Valley – 2012, at http://aic.ucdavis.edu/almonds/cost%20studies/AlmondSprinkleSV2012.pdf ,

The total annual volume of water for 50 acres is 3.33 * 50 = about 167 AF/year.  That equates to a constant flow of 0.03 cfs.  But, you probably irrigate one day per week, so 7 times the average rate = 0.21 cfs. So, in your permit application, you would need to apply for 167 AF/year, diverted at a maximum rate of 0.21 cfs.

To get the rate for filing for a permit with the Board, we need to check the fee schedule:   http://www.waterboards.ca.gov/waterrights/water_issues/programs/fees/docs/fy15_16_fnl_fee_schd_sum.pdf

SWRCB_fee_summary_permit_app

So your application fee would be $1,000, plus $15 per AF over the first 10 AF.  Your cost would be $1,000 + (167 AF – 10 AF) * $15/AF, for a total of $3,350.  There is also an annual cost:

SWRCB_fee_summary_permit_annual

Your annual fee would be $150 + $0.063 per AF over the first 10 AF.  Your annual cost would be $150 + (167 AF – 10 AF) * $0.063/AF, for a total of $160/year.

Of course, these costs are if it’s a “slam dunk” and there are no complications.  There would likely be a 1602 permit required by the California Department of Fish and Wildlife, and there could be other permits.  If anyone contests the application, then you would have more fees (see the schedule), perhaps attorney fees, and perhaps a negotiation to use water from someone else’s diversion.

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