Sterling: “AgFest” recap

May 10, 2014

Groundwater movement via the USGS

Groundwater movement via the USGS


From the Sterling Journal-Advocate (Callie Jones):

This year’s festival included 10 stations, including the GPS mapping station, where Morgan County Extension Agent Marlin Eisenach spoke about how farmers use GPS mapping to plow, so they don’t use too much agricultural herbicide or insecticide and they can save as much fuel as possible…

At the groundwater station, Extension Agent Molly Witzel, from Burlington, spoke about watershed, an area where smaller bodies of water flow into bigger bodies of water; an aquifer, “a big underground lake;” and other groundwater terms. She also spoke about what happened during the South Platte River flood last fall…

A rangeland ecology station had students learning about the different plants and animals that can be found on rangeland. Logan County Extension Agent Casey Matney talked about the importance of rangeland, because it has trees, animals and water.

At a plant science station the fifth graders learned about the difference between dicot and monocot plants, they got to see different types of seeds and they learned about how plants grow.


Sterling: ‘The plant is doing what it was built to do’ — Jim Allen

January 12, 2014
Reverse Osmosis Water Plant

Reverse Osmosis Water Plant

From the Sterling Journal-Advocate (Sara Waite):

…Allen said they have yet to receive any reports of discolored water, and there is no evidence of issues with lines breaking due to the new water. He said he didn’t believe a problem last week with the service line to Pizza Hut was due to the water treatment system, although he acknowledged it would be hard to prove either way. But, he said, when the problem arose and city crews dug up the line, they found it was an old lead service line, which they usually replace anyway with newer materials.

Allen was reluctant to talk about the probability of those problems — he said he doesn’t like to discuss things he doesn’t want to happen — but he was happy to report that the uranium levels in the water, which prompted the need for the new treatment plant, are falling. The membranes (in the reverse osmosis system) are working, he said.

He said that the newly treated water likely has not fully replaced the “old” water in the system, as it has to cycle through the storage tanks and into the water service. The timeline on that depends on the volume of water in storage and usage.

The water is safe to drink, he reiterated.

“The plant is doing what it was built to do,” he said.


The price tag for Sterling’s deep injection wells for RO brine escalates from $80,000 to $2.3 million

March 29, 2013

reverseosmosiswaterplantschematic

From the Sterling Journal-Advocate (David Martinez):

[Sterling Public Works Director Jim Allen] told the council that Public Works was working on a number of water and sewage issues around the city – most of them directly or indirectly related to construction of the new water treatment plant.

The one that stands out: Deep injection wells used to pump the treated wastewater from the reverse osmosis filtration, estimated to cost $80,000 at the start of the project, will now cost about $2.3 million, according to a March 10 estimate. About $1.3 million of that cost would go toward the construction of one of the two pumps, which is located above the railroad tracks north of the plant…

The wells themselves, buried about 7,000 feet underground, have already been constructed. They were included in one of three bid packages for the project – the other two being a pipeline project and the water treatment plant itself, which is in the final construction stages.

Allen told the council the increased cost comes from the pumping equipment needed, as well as some stainless steel piping needed for the aboveground operation. The pipes might need to handle 2,200 to 2,600 pounds of pressure per square inch, which Allen said is a “monumental number.”[...]

Allen told the Journal-Advocate the $2.4 million also isn’t set in stone; he, Kiolbasa and others will be working with the estimates for a more solid cost…

In related projects concerning the plant, Public Works is continuing to redrill and rehabilitate the city’s raw water wells. The effort is part of a plan to have enough raw water to actually put through to the water treatment plant.

In February the council heard that the plant planned on having the ability to pump more than 7,900 gallons of water per minute, but that it could only pump about 5,500 gallons at that point because of degraded wells.

More infrastructure coverage here.


Sterling: New reverse osmosis treatment plant to be online by late summer

February 7, 2013

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From the Sterling Journal-Advocate (David Martinez):

Some unexpected hang-ups have pushed back the time before residents receive the full benefits of the new water treatment plant until late summer. The plant has been filtering the city’s water since November, but the full 80/20 reverse osmosis (RO)-filtered water to regular filtered water mix will eke its way into Sterling’s system over the next several months…

The water treatment plant will significantly lower uranium and pollutant levels, and significantly drop the hardness of the water.

Most of the issues crews ran into concerned well and distribution issues, but one stood out: A thick, black, non-cohesive material in the well water was clogging up filters faster than expected. “We don’t know entirely what it is,” said Rob Demis, of Hatch Mott MacDonald, the company overseeing construction of the plant. He brought a bottle of it to show the council, showing it as fine black sediment layered at the bottom of clear ground water. After a couple of shakes, the water turned black and opaque. The material – 20 percent organic material and 30 percent manganese, with traces of other elements, such as iron and silicon – is also odorless, though Demis guessed it would have tasted “metallic” and “bitter.” The manganese gives the material its color.

The raw water filter running now, which catches sediment down to the one-micron level, has caught the material at the five-micron level. Crews would change the filters every couple of days in November, but it’s since become less prevalent, which Demis credited to the city’s aggressive pipe flushing program. “We don’t know the origin. It may be coming out of the pipes. It may be coming out of the formations,” he said. “The good news now is we’re filtering it.”

The plant also encountered issues with its distribution system, which wasn’t getting water out of the plant quick enough to the city’s distribution tanks to fill them. Demis said the plant quickly fills Sterling’s north and south tanks but doesn’t reach its west tank. Part of the problem might be buildup in the pipes over the years slowing water flow (like plaque clogging an artery, Demis said), but many of the pipes are also 100 years old…

The plant had planned on having the ability to pump more than 7,900 gallons of water per minute, but right now it can only pump about 5,500. That means that of the treatment plant’s three pump levels – the third allowing the maximum amount of water to pump during peak use – they can only pump enough water to fulfill the first two…

Water treatment crews have also been finishing construction on two deep water injection wells, which will deposit treated waste water more than a mile underground. One of the wells was dug at about 7,200 feet underground, as recommended by EPA estimates, while the second was dug to about 6,100 feet.

Demis said the area’s geology hasn’t been fully explored, so the crew will need to test the area over time.

More infrastructure coverage here.


South Platte River Basin: DWR Sterling Groundwater Monitoring Effort

January 22, 2013

vibratingwirepiezometer.jpg

Click here for the Sterling Groundwater Monitoring Effort website from the Colorado Division of Water Resources. They write:

Homeowners have relayed their concerns about high groundwater levels in the Country Club Hills and Pawnee Ridge subdivisions in Sterling to state officials. The DWR and CWCB are conducting an independent analysis at each subdivision. The agencies have undertaken an effort to monitor groundwater levels and characterize the hydrogeology within the areas of interest. The objective of this groundwater monitoring is to identify relationships between the hydrology of the area and the high groundwater levels. Preliminary information and data obtained from this investigation is updated monthly.

Here’s a report from David Martinez writing for the Sterling Journal-Advocate. Here’s an excerpt:

Ralf Topper, senior hydrogeologist at the DWR, said at a community meeting that results so far show that a mix of geologic deposits and structure – in terms of bedrock – have an effect on the level of water tables.

Several area farmers and residents have complained of low water tables, or levels below ground that are completely saturated with water. Spots with water tables as high as at four of five feet below the surface can damage crops and cause basement flooding.

So the DWR and the Colorado Water Conservation Board started conducting an independent analysis of the city’s subdivisions.

The agencies are monitoring groundwater levels and characterizing the hydrogeology around the city. The goal, according to the DWR, is to find relationships between the area’s hydrology and the high groundwater levels.

“We’re looking at all of the inputs and outputs,” Topper explained. “Why are groundwater levels changing? What’s the mechanism for changing?”

He added that they’ll collect data on stream flows, diversions, recharge ponds, climate and large capacity oil pumping. All of that will then go to third party consultants to analyze.

The DWR has studied 16 piezometers – devices that measure groundwater pressure – between the Sterling subdivisions of Country Club Hills southeast of Northeastern 18 Golf Course and Pawnee Ridge north of County Road 30 and east of Ballpark Road since May.

From the measurements, the DWR found that the geology from spot to spot varied between thick and thin layers of gravel, sand, clay and shale (bedrock).

The clay is important, Topper said, because water levels where clay exists tend to be shallower.

“(The results) gave us an indication that we’re really looking at a system that is highly variable in terms of the subsurface,” he said. “The assumption was (the land’s) homogenous…. Everyone says it’s sand and gravel. What we’re finding in this area, it’s not the case.”

And the water tables can vary in any given spot, as well.

“Nested” piezometers, which measure at different levels from the same bore hole, showed that water tables existed in as many as three layers in Country Club Hills. Some tables were as shallow as three feet, while others were as deep as 24.

More South Platte River Basin coverage here.


Sterling: New reverse osmosis water treatment plant online and ramping up to full production

January 6, 2013

reverseosmosiswaterplantschematic.jpg

From the Sterling Journal-Advocate (David Martinez):

…by the end of February, [city engineers] say, 80 percent of the city’s water will run through dozens of stacked reverse osmosis (RO) filters, squeezing out pollutants to meet state standards.

“It’s not something you call in and say, ‘Hey, deliver this to us,'” said Mark Youker, construction manager for Hatch Mott McDonald, which has overseen the architecture and engineering of the project. “It’s a lot more complicated than that.”

Plans to build the plant started around September 2008, when the Colorado Department of Public Health and Environment issued an enforcement order to get the city’s water standards up to compliance within a given time frame. The main contaminant, among others, was the water’s naturally-occurring uranium levels, which could increase an individual’s cancer risks over longer exposures.

Youker said before the plant was constructed, Sterling’s water was pumped directly from wells across the county, treated with chlorine at four separate stations and delivered directly to city homes, farms and businesses.

When the plant becomes fully operational, the city’s raw well water will all instead flow straight to the one spot for treatment. It’s capable of providing 9.5 million gallons of water to the city per day, though the average demand is only about 4 million gallons.

The water will run through a filtration system before it’s chlorinated, and be pumped out as a 80/20 mix of RO-treated to untreated water; Youker said the city has been receiving the “20 percent,” filtered water for about two months already.

Workers at the new Sterling Water Treatment Plant monitor every aspect of the treatment process through a monitor in their control room. (David Martinez/Journal-Advocate)
Ryan Walsh, the project engineer, said the mix holds several structural and taste benefits.

“The first goal (of treatment) is to bring the city’s water to compliance with the new state standards,” Walsh said. “The second is to bring water that more aesthetically pleasing and requires less maintenance.”

More infrastructure coverage here.


Logan County approves data collection monitoring well license for high groundwater levels

May 9, 2012

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From the Sterling Journal-Advocate (Judy Debus):

The Logan County Commissioners once again considered a request by the Colorado Water Division to use county-owned property for the installation of monitoring wells for data collection in the groundwater-plagued area of Pawnee Ridge Subdivision and Country Club Hills. Commissioners Jim Edwards, Dave Donaldson and Debbie Zwirn were present for Tuesday’s meeting.

At a previous meeting, the request was addressed in a license agreement, but was tabled due to language problems. This week, the request from removed from the table upon motion by Edwards and then postponed indefinitely. To replace the requests, commissioners then approved lease agreements (rather than license agreements) to provide the approval for the wells to be installed. The data will be collected and then analyzed to determine the cause of the increased groundwater problems in the two areas.

The CDW held a public meeting last month to present their outline of a program to address the water issue. That program will begin with the monitoring program that will last a period of two years with an initial analysis at the end of one year.

More South Platte River basin coverage here and here.


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