When it rains, it can pour, but in the world’s drylands the net result can be disastrous: flows of water washing away useful soil and what little gets left behind dries up, forcing locals to take long treks to find more during dry seasons. Unless, that is, these flows are stopped by sand dams.

Sand dams are simple but effective on multiple levels. Like normal dams, they involve walling off areas where water flows — channels that turn into streams and rivers when it rains. They trap water (up to millions of gallons per dam), which can sink into the sand for longer-term storage above the dam (then be tapped via pipes below).

Sand dams also help keep valuable soil in place, preserving and creating new areas of arable land around them. The sand also helps filter and protect these water sources from contamination and disease.

So far, the charity pioneering these (called Excellent) has worked in multiple countries across Africa to construct around 1,000 sand dams, but they are branching out, too, aiming to take this technology to South America and South Asia as well. Their strategy is to partner with communities, helping them build out sand dams and spread knowledge of their construction as well.

“Sand dams transform lives,” explains the charity. “They provide a sustainable, clean, local source of water for rural communities, saving time and creating opportunities for farming, education and poverty alleviation. By breaking the cycle of dependence Sand Dams create choice; freeing people to realise their own potential.”

A fresh new type of park-on-the-water in Rotterdam is turned plastic trash that once polluted the area into a series of hexagonal pods now open to the public. The design is built to scale, too — more units can be added as more waste is recovered.

The floating landscape is meant to raise awareness, but also provides a practical resting spot for people, as well as a refuge and breeding ground for snails, flatworms, beatles and fish — each pod has its on purpose, be it benches for humans or soil for plants and animals.

The artificial island chain was built by the Recycled Island Foundation, an organization that takes trash from the mouths of rivers using litter traps and reuses what they can. These traps are designed to catch and keep what passes by, even as the currents of the rivers change.

“When we retrieve the plastics directly in our cities and ports we actively prevent the further growth of the plastic soup in our seas and oceans. The realization of the building blocks in recycled plastics is an important step towards a litter free river.”

This robotic “smart” planter wanders around on six articulated legs to make sure your precious greens get enough natural light, prompting the observation: “This is called a cat. You’ve invented a cat.”

And there’s something to the comparison — cats self-regulate, so why not plants? Heliotropism draws plantlife naturally to the sun for nutrients, causing owners to shift around their habitats, but there’s no need with this bot. It can even stomp to demand water, like an impatient pet.

Developed by Vincross in China, the self-optimizing micro-robot can walk around and make sure any houseplant gets sufficient sun or shade. The HEXA was originally a simple walker, until its inventor put a pot into it.

So the whole thing may seem (and be) a bit silly, but it does add some interactivity to a home, particularly for people who aren’t around enough to take care of animals (or perhaps even an idle houseplant). Also, it’s a pretty good way for a robotics manufacturer to get people interested in their products.

“Robots are THE next big platform. We’ve all dreamed of a world where robots interact with and help humans in their daily lives. But the reality is, robots have a long way to go. Limited access — robots are either too expensive and complex isolated to a lab or too simplistic, a child’s toy — has kept innovators, explorers and the masses at bay.”

“Meet HEXA, the first of a new generation of accessible, programmable robots from Vincross. HEXA is a six-legged, highly maneuverable, compact robot that comes complete with all the necessary sensors. Along with HEXA, we deliver MIND, a robotics OS and SDK, where for the first time individuals don’t need to know underlying hardware and complex mechanics to learn and create interesting robotics functionality.”

Standing nearly 40 feet tall, this giant arcing whale is composed entirely of plastic waste gathered from the Pacific and Atlantic oceans, carefully assembled in a canal of Bruges, Belgium.

Following a Liquid City theme, Brooklyn designers from STUDIOKCA chose the form to help observes visualize the magnitude and shape of both what winds up clogging the world’s oceans and the creatures impacted.

The net effect is striking, the arched water mammal rising up from the deep in a graceful curve, which, upon closer inspection, is made up of white and blue refuse, stamped with languages and brands from around the world.

Dubbed Skyscraper, the sculpture brings together 4,000 square feet of discarded plastic gathered in Hawaii beach cleanups, a small fraction of the 150 million tons currently lost at sea.

And while the majestic sea creature ricing from the canal might seem large, “pound for pound that is more plastic waste swimming in the ocean than there is whales,” say the creators. “So an opportunity like this to show the type of plastic and the amount of plastic that ends up in our oceans is really important.”

A new first-of-its-kind underwater art museum in the Maldives features exhibits and sculptures at various levels, from the seabed through the intertidal waterline and up to the skyline, designed to be exposed and submerged to different degrees.

More than just an aesthetic endeavor, however, the project by environmental artist Jason Decaires Taylor is engineered to support the regrowth of endangered coral populations and other local marine wildlife. It’s the island’s first regeneration project, addressing a real need while also raising regional awareness.

The outer shell is a permeable, stainless steel structure, with some above-water sculptures placed on top. Below, divers can visit works made of marine-grade cement that will, over time, become covered as sealife attaches to it.

Visitors will be able to follow a path from the shore along which they can explore local sea life in the shallows before reaching the museum, a symbolic journey from land to low water and into the deep beyond.

The intentionally porous frame of the main museum building allows in even large fish, while also providing a tidal break to help shelter any creatures who choose to take up residence (or simply find temporary refuge) within.

Marine steel mirrors and mimics surrounding sea blues, and will ultimately also reflect the greens of the natural algae bound to accumulate as this seed structure naturally changes and grows in response to its environment.