Some rainwater harvesters like the look of a plastic tank or a silver metal culvert cistern that announce that they are saving water.

Others want to be less obvious. Kay Baumann is one of them.

“I was a little shy to have two big plastic tubs in my backyard,” says the north-sider.

Instead, she took the advice of permaculture designer Justin Bramhall and covered two plastic tanks, which store a total of 2,185 gallons, with gabions.

A gabion is a metal cage filled with rocks.

For Baumann’s tanks, Bramhall, owner of Ahimsa Landscaping, put the tanks on the ground, then encircled them with the cages.

He used up to 8 tons of rock to fill the cages. He then topped the tanks and the gabions with metal lids that are often used for metal-culvert cisterns.

The rocks help the tanks blend into the landscape because they are the same color as the fences around the backyard.

Plus, they match the landscape design, which includes flagstone walkways, rock planters and native plants.

“Rocks are very commonly used as decor in your yard,” says Baumann. “I thought it fit into the decor very nicely.”

The rocky facade doubled the cost of installing the tanks, part of a complete water-harvesting installation that included gutters and underground pipes.

Baumann says some of that additional cost will be covered by a rebate from Tucson Water.

The gabions make it hard to get to the tanks if a leak needs to be patched, says Bramhall. To get to a tank, the frame has to be cut and the rocks removed.

But if cost and access are the downsides of covering tanks with gabions, Bramhill sees a number of advantages besides aesthetics.

By shielding the tanks from direct sun, he expects them to last far beyond their 10- to 20-year warranties. The protection also regulates the temperature of the water in the tanks, eliminating scalding or freezing issues.

And the rocks themselves hold and radiate enough heat that they create warmer microclimates that protect sensitive plants from frost or freeze damage.

Baumann hopes to soon plant ivy that will cling to the metal cage as it would to a trellis. “I want to make it a big bush.”

Midtown resident Nicolas Siemsen also wants to embellish his uncommon 1,300-gallon rainwater-harvesting tank.

The 2-year-old ferrocement, or reinforced concrete, structure currently has a stucco finish. He hopes to soon cover it with a mosaic designed by his mother-in-law, who does tile work as a hobby.

Concrete can be made to match any landscape style, he says. It can be colorized, painted, inlaid with a variety of materials or finished in different textures.

Like Kay Baumann’s water-harvesting system, Siemsen and his wife collect rainwater from their home’s roof with gutters that guide water through underground pipes to the cistern. That way the storage tank doesn’t need to be close to the house.

For the Siemsens’ tank, a concrete pad was laid. Rebar was shaped into a cylinder. The frame was wrapped in chicken wire and peg board. Concrete was spread over the metal and wood structure. The interior was sealed with a potable water-grade coating.

The Siemsens agreed to install the tank as a demonstration project for the Watershed Management Group, which helps people work together to complete sustainable living systems for the cost of materials and consultants.

But the couple also liked the idea of trying something different.

“We fell in love with the potential for a different-looking system and a longer-lasting system,” says Siemsen.

A ferrocement cistern is expected to last 100 years, although it eventually develops superficial cracks that require maintenance.

With cement, the Siemsens were able to shape the cistern in a way that could collect a lot of water without making the tank so high that a building permit would be required.

“We wanted volume (of collected water) with something that’s less imposing than metal,” he says.

While they used a conventional cylindrical shape, Siemsen says ferrocement allows water harvesters to create any type of shape, including those that can provide other functions, such as retaining walls.

Randy Young, a Tucson general contractor and master auto mechanic, is working on a rainwater-harvesting modular system of concrete walls that could be built throughout the landscape.

Young calls his idea Walls 2.0, which could turn “landscape and security walls, facades, gazebos and ramadas” into water-storage tanks, according to his website.

His system will essentially hide water harvesting, something he feels homeowner associations can embrace.

“Neighborhood associations are not allowing people to put tanks in their yard,” Young says, adding that he has removed tanks for residents who did not have permission to have them.

“This definitely has dealt with that,” he says of his idea.

Young hopes to get enough funding so that in the spring he can construct a prototype at Watershed Management Group’s Living Lab and Learning Center, a demonstration site at 1137 N. Dodge Blvd. that is under construction.

Contact Tucson freelance writer Elena Acoba at