Beginnings, Ponds, Rivers, Falls and Retaining Walls

Water is life. But while everything living on Earth depends on it, as residents in a particular geography we don’t often give much thought to our local sources of water—at least until there’s a shortage.  

On Salt Spring Island, we are subject to a boom-bust cycle of seasonal rainfall and drought. We have a big reputation for water shortages, drought conditions, and water rationing during the peak of summer. 

At Cusheon Lake in July precipitation averages less than a millimetre a day, and the creek that runs south out of it is often completely dried up by late summer. In November, by contrast, we get around 190 millimetres in one month⁠1 and streams all around the island are flowing like whitewater, carrying all that life-giving water to the sea.  

The not-so-good news is that this wet-dry cycle is poised to get more extreme due to climate change. In 1980, for example, there were 28 days with less than one millimeter of rain. In 2020 there were 33. This is predicted to rise to 40 days per year and beyond within this century. Rising temperatures and rainless days will have far-reaching effects on farms, gardens, recreation, forest habitat and wildlife. 

The heat dome and atmospheric rivers of 2021 showed us all a taste of the extremes we will have to deal with in the future. 

Salt Spring Climate, Rainfall, and Water Storage Solutions

The good news is that on Salt Spring we live in a temperate rainforest and we don’t have a water problem! We receive an abundance of water here, as the rushing streams of November attest.

Rather, we have a storage problem. We need to start keeping more of our autumn and winter rains on the island, instead of letting them run straight into the sea. We need to protect forests and freshwater ecosystems, yes—and we also need rainwater harvesting and wise water-management practices. 

If we invest in planning and infrastructure that suits our geography and climate, we will all be far more resilient in the face of wetter autumns and winters and hotter, drier summers.   

Educating ourselves on how to manage water has been a major priority for Lightwater. Our approach has been to try to better understand the sources and flows of water all around us, in hopes that we’ll become better stewards of what is without question the world’s most precious resource.

Harvesting rain and corralling run-off

The water that runs around and beneath our property—and indeed, all of Salt Spring—imparts a vibrant, sacred and “alive” quality to the land. We’ve been honoured to build our farm and grounds around core principles of water stewardship. 

What that means in practice is that via roof harvesting, streams, culverts and pump systems, we are channeling surface water—rain—into an array of ponds and underground cisterns. Instead of water running off the land and into the sea, we are creating catchments and a pump system to keep more of the water on the land for longer.  

Rainwater harvested from rooftops is returned to the landscape via perforated underground pipes. Some rainwater is also directed into Lightwater Pond, which receives additional water from two other sources: underground catch basins that collect run-off from King Road; and “perched” water—water that is cut off from the main aquifer by layers of granite beneath the property. 

All of this water would otherwise run straight into the ocean. In summer we are able to redirect more than 1400 gallons of it per day. It can then be pumped back up the property to our cisterns and to Elm Grove Pond to keep them full.

Practical oases: irrigating while preventing fires & erosion

Named for the rare copse there that has survived outbreaks of Dutch elm disease since the 1920s, Elm Grove Pond holds 1.3 million gallons of water. This pond was a water asset for local residents from the late 1800s up until the 1960s, and we are working to restore it to its role as a viable source of freshwater for multiple uses. 

Another 40,000 gallons are stored in two underground cisterns, and Lightwater Pond south of the main guest house is a 100,000 gallon reservoir for orchard and flower bed irrigation. 

The ponds created by our water system offer scenic oases for guests and the public to enjoy, but they serve another core purpose: conservation. Lightwater shares the South Central Salt Spring Island aquifer (also known by the catchy name of Aquifer #1147) with others on the southern lobe of the island; because our ponds and cisterns supply our irrigation water, they drastically reduce the amount that an acreage of this size would typically draw from it. (For more on aquifers and groundwater, see below!)

Redirecting surface water from running into the sea also prevents erosion. High flows during storm events can cause erosion and affect the stability of slopes. Prior to remediating the Lightwater beach area of buried trash and creosote-leaching pilings and creating a culvert system—which will now be redirected via pumps to pull water into our storage ponds—erosion was eating away at the foreshore at a rate of one and a half to two feet per year. 

Ultimately, water storage will also assist in preventing the spread of forest fires in our neighbourhood. This part of the island— like much of Salt Spring below its northern one-third— is in terrain flagged for “extreme” fire risk. As with our water stewardship, we take our role as a fire-break seriously. Along with storing water to assist in potential community fire suppression efforts, the Lightwater property has been cleared of gorse and broom, pesky invasive plants that are known fire accelerants.  

Elm Grove Pond is just being completed, and along with a bench where residents can sit and enjoy the view, it will offer a community notice board and postal boxes. This is just one way that water brings us all together, and shows us how much we have to gain by thinking holistically—and practically—about how to manage it for community resilience.

Some questions about freshwater ecosystems answered

Want to know a bit more about freshwater ecosystems? Here are answers to some questions we’re often asked.

What is groundwater? And what’s an aquifer? 

Those of us in rain-drenched temperate regions often assume all water comes from the sky. That’s true in some sense, but it’s not the whole picture. 

On Salt Spring water comes from above in the form of rain, but it is also present below our feet in the saturated layer of rock and sediment called an aquifer. Most aquifers are not giant underground lakes, as we might imagine. They are simply vast areas where the spaces between rocks and particles are filled with water. 

This may not seem like much water, squeezed into these tiny areas, but it is: if all the world’s groundwater were brought to the surface, we’d be swimming in a layer of water wrapping the earth to a depth of 180 meters⁠2.

Water in an aquifer is known as groundwater. The water table, a term you’ve probably heard, is simply the top of that saturated layer we call an aquifer. Dig a hole deep enough and water will start to puddle around your feet. That means you’ve hit the water table, the groundwater at the top of the aquifer. 

How are aquifers fed? 

Water that is not lost to evaporation, but instead is able to sink down through soil and substrates to end up in that saturated layer called an aquifer—that is how aquifers are replenished. 

In a typical flat parking lot, rainfall doesn’t permeate it; water either runs off to be culverted, usually into the ocean, or it evaporates. In both cases, water can’t make it into the soil and ultimately into the aquifer that lays up to 100 metres below the surface. 

Forests, fields, yards and all permeable ground surfaces have the potential to allow water to feed the aquifers deep beneath our feet. This is why we need to balance development with conserving land and wild spaces that will allow rain to replenish our shared aquifers. 

Water wisdom in practice

Our cisterns, pumps and ponds work in harmony in order to store plentiful rains for use in the summer and keep the amount of aquifer water we draw for irrigation very low. We’re pleased that the system meshes very well with the freshwater goals of Transition Salt Spring’s 2021 Climate Action Plan:

1. Protect freshwater quality and quantity
2. Improve summer freshwater availability
3. Reduce fire risk 

As the effects of climate change become more pronounced, we can all benefit from the water wisdom and careful stewardship that groups like Transition Salt Spring are encouraging in communities across the island. Together we can all play a part in building resilience and preserving its character, beauty and biodiversity for future generations.