Kristina G. Fisher and Andy Otto
As we work to secure Santa Fe’s future in a changing climate, one crucial element will involve adapting to a new water reality.
Among the many expected effects of climate change is a shift in precipitation patterns. In the coming years, Santa Fe will likely receive more rain than snow, and this rain will likely fall in fewer, heavier storms. Rainstorms like the ones we have seen the past couple of years, during which several inches of rain fall on the city in an hour or two, will become increasingly common.
This change brings two major challenges. First, heavy rainstorms can cause serious damage to public and private property, flooding roads and homes, undermining bridges, eroding and washing away pipes and utility cables. Repairing and replacing this damaged infrastructure is a growing expense for both the city and individual Santa Feans.
The second challenge is storing enough water to meet our needs in the coming years. When our water arrives as snow, or in small rainstorms, it has time to gradually soak into the ground and recharge the aquifers that still supply a good portion of our drinking water. When several inches of rain fall all at once, the water flows rapidly out of the city, out of the watershed and out of our hands.
To help us meet both of these challenges, we have an often-overlooked ally: our arroyos.
Hundreds of miles of arroyos wind their way through the Santa Fe Watershed. When rain falls on the city, it runs swiftly off paved, impermeable surfaces and ends up in the arroyos, which eventually empty into the river.
For many years, arroyos were viewed simply as stormwater channels to move water quickly off the landscape and prevent flooding. Unfortunately, this strategy led to significant erosion of arroyo banks and beds, because the faster water moves, the more force it has to carry away soil and rocks—and to wash out roads and bridges.
A 2012 assessment commissioned by the city and performed by the Santa Fe Watershed Association (Arroyo Assessment Surveys of 10 Major Arroyos in the Santa Fe Watershed, November 2012) found that in many areas, arroyo erosion threatens critical infrastructure, including trails, roads, bridges and even homes. Erosion has also exposed pipes and electrical cables in a number of arroyo reaches, creating threats to public safety.
While flash-flooding arroyos are serious hazards, arroyos are also important resources: They are the low places in the watershed where water can most easily infiltrate into underground aquifers. Restoring Santa Fe’s arroyos therefore provides us with our best opportunity, not only to prevent damage from major storms, but also to capture and store water so that it will be available for us during dry years.
The Climate Action Task Force has recommended that the city of Santa Fe develop a comprehensive plan for restoring our arroyos with an eye toward achieving both of these goals.
We envision restoration strategies that would focus on “green infrastructure,” such as the induced meandering techniques used in the Santa Fe River (e.g., one-rock dams, boulder cross vanes and Zuni bowls). These sorts of structures, developed by restoration experts like Bill Zeedyk, slow water down and spread it out. As the water slows, the sediment it is carrying drops out, raising the streambed. As the bed rises, it creates more space to store water and allow it to sink gradually into the aquifer. In addition, as the water slows, its destructive power diminishes.
The city and the Santa Fe Watershed Association are currently preparing to update the 2012 arroyo assessment with an eye toward prioritizing the areas where restoration projects are most feasible and most urgently needed. The plan would pinpoint where infrastructure is currently at risk and begin to analyze where aquifer recharge would be most effective, based on the underlying geology.
Santa Fe’s arroyos are everyone’s backyards. They are pathways for kids walking home from school, wildlife traversing the urban landscape, and our utility pipes, cables and lines. How many times have you heard someone tell a story that begins “out in our arroyo last week…?” We all own them, we all know them, and now it is time to come together to protect and restore them so that they will help us secure our water future in a changing climate.
Kristina G. Fisher serves on the Climate Action Task Force and is president of the board of the Santa Fe Watershed Association. Andy Otto is executive director of the Santa Fe Watershed Association, which uses education, restoration, stewardship and advocacy to protect and restore the health and vibrancy of the Santa Fe River and its watershed for the benefit of people and the environment. www.santafewatershed.org