Ever wonder why humans chose to settle in San Francisco? Perhaps it was the views of the Pacific and the Bay, the temperate climate, or the gold in them thar hills. Another not so obvious answer is that San Francisco is sitting on a wealth of water, from underground aquifers, to rivers, lakes, and creeks. While our local watershed has long since been paved over, this priceless resource still flows, trapped beneath the concrete that supports our steps.

Through time immemorial human animals have settled near water. Traditionally, out of necessity, we have followed the water that cycles the earth; evaporating from the oceans, captured in the clouds and rained onto land, settling in reservoirs, rivers, lakes, soil, and below-ground artesian streams. Where water falls life springs forth, soil becomes fertile, plants grow and animals gather to eat and drink. Where water falls is the watershed, and like all things sustainable, watersheds are local. Brock Dolman, local water expert, explains that a watershed is a “basin of relationships” between the earth, plants, and animals --a bio-region. Perhaps humans settled in San Francisco because of its water resources.

But if watersheds are local, then why does 95% of our water come piped in from the Hetch Hetchy reservoir, 165 miles away in Yosemite National Park? It seems logical enough, knowing that San Francisco is surrounded by salt water and has a short rainy season. Is it not necessary to get our water from the dammed Tuolumne River, whose water fills what once was the Hetch Hetchy Valley, described by John Muir as equal in beauty to the Yosemite Valley? If we consider that humans have lived here far longer than Hetch Hetchy has been a reservoir, the mystery of our local watershed becomes more poignant.

In 2004, Joel Pomerantz documented the politics and the history of the San Francisco watershed in an article entitled “A Clean Little Secret”. Pomerantz cites numerous creeks, multiple lakes, and even a river that run through our city. The following description is a hint of just one of the many water resources that we walk upon today, but know little about:

On April 5, 1776, Juan Bautista de Anza's party rowed up Mission Creek from the bay to establish a mission. April 5 is the feast day of Our Lady of Sorrows (Nuestra Señora de los Dolores)—thus the name Mission Dolores. The creek they entered wound through marshes to a tidal lagoon and then into a flowing freshwater lake, called Laguna de Manantial. The creek probably spanned a width of forty feet or more and, at 100 to 200 cubic feet per second, offered enough current to require real effort in the arms of the rowers. The water was sweet and excellent for drinking (as it still is today).

For hundreds, and perhaps thousands of years, the humans that lived in the geographic location we call San Francisco drank from the flowing creeks of Mission, Islais, San Souci, and Lobos; from Lake Merced and Lake Manantial; and from the Hayes River. There was no need for Hetch Hetchy because, in fact, there was a natural system of navigable, fresh water that flowed down the slopes of the Presidio and Twin Peaks and settled in basins throughout the city.

We now live in an era of globalization and under a prevailing mentality that large scale solutions will solve local problems. It could be this attitude that allowed a project like Hetch Hetchy to reallocate local watersheds. As a society, we are frightfully disconnected from nature. Whether we are talking about food, energy, or water, we have been programmed to believe things are the way they are for a good reason, period. Resources appear to be available to us without limits, so why should we be concerned to preserve them?

To add more clarity to the picture, we should think not only of the long distance that water travels to our taps, but also what happens to it once it goes down the drain. Our city is for the most part impermeable, covered in asphalt and concrete. Almost all of the rain that falls locally goes directly to the “storm drain”, a.k.a. the sewer, the same place that our showers, sinks and toilets drain. According to Pomerantz, over 2.5 million gallons of potable water flow weekly from the Hayes River into the Powell Street Bart station, where it is pumped by the transit authority, also into the sewer, to prevent the subway from flooding.

It isn’t feasible to unearth our watershed by tearing up the city, but looking outside of our reality, it is easy to see why as individuals we should do something to correct the problem and lead more sustainable urban lives, especially where our seemingly limitless water is concerned. If we take for example the fact that for the last 3 months much of the North American continent has been suffering from a severe water shortage, our perception of water abundance is changed. If we consider that women in Africa and other parts of the world walk miles to a water source and carry the heavy burden home, we can imagine another water reality. Yet another water reality surfaces, in Yemen, where families are obliged to spend up to half of their daily income on water sold at markets.

To really understand what we are doing wrong, though, it helps to know how water works and why our current patterns of water consumption are unsustainable. First, we should know that the natural flow of water is to take the path of least resistance, winding in sinuous, meandering patterns, with the flow of gravity. Water, much like tree branches, or plant roots, or our own nervous and digestive systems, flows in circuitous paths. Realizing this, we understand that to pump water up from underground pipes or in straight lines is unnatural and inefficient. Why not capture rainwater from roofs and let it flow downward?

Next, we should understand that water is the fundamental compound necessary to life. Our bodies are composed of 60% water. The earth is 70% water, but of that only 3% is fresh water and another one percent is locked under the earth’s surface and in glacial bodies. Most of the fresh water streams, lakes, and rivers that wind through our planet are polluted by the industrial processes that facilitate our modern lifestyles. The reality is that water is a scarce resource and not the limitless elixir we often take it to be.

If we still don’t get it, we might consider that water is responsible for 70% of the world’s illness. Scholar and engineer Luna Leopold said that, “the health of our water is the principal measure of how we live on the land.” To prevent waterborne disease, our tap water is treated with toxic chemicals, in our case chloramines, to kill pathogens before they can harm us. Chloramine kills pathogens, fish, and birds, but decision making authorities have decided that it will protect us. Go on, have a drink of some of your clean, clear San Francisco water, but remember Leopold was right.

Now when we consider the under-use of our local watershed and the miles and miles and miles of pipes that bring us water, it becomes evident that our water resources have been disrupted and redirected in an over-engineered system that not only can’t sustain itself, but is also bafflingly wasteful. From this understanding, we can take action to re-localize our watershed. For examples, we can look to communities like Village Homes in Davis, CA, a community designed to produce zero net runoff, that is no storm drain. Instead, greenways, gardens, and food producing trees absorb runoff. Contoured swales form creeks that flow below pedestrian bridges. Water cools the community and is cycled back into nature. Or we can turn to groups like the Oakland based Greywater Guerrillas, that believe we should all disconnect from the sewer and stop throwing our water away. Or the Surfrider Foundation that sponsors projects supporting the removal of impervious surfaces, such as parking lots, and replacing them with planted driveways that can absorb runoff and pollutants. This is the mental shift that will lead to sustainable water usage.