Rainwater Collection: Past and Present
An exploration of the projected salt water intrusion, with a look at the history of rainwater collection in NOLA.
If a record–breaking summer in terms of extreme temperatures and low rainfall wasn’t challenging enough, the looming salt wedge creeping its way up the Mississippi River feels like a wake-up call. Even as city officials urge us to stay calm and go about our business, some of us in the ecological world are feeling frenzical. It’s time to transform that frenzy into action through creativity, research, and commitment to our values as plant-people.
Of course, we are humans before we are gardeners, and we deeply value human health and safety. This is not an effort to belittle public health risks associated with the wedge. It is merely a plant and environment- focused perspective. First, let’s hit some of the facts. What exactly are we facing as gardeners and growers? According to the National Weather Service, October and November are the two driest months of the year in the New Orleans area. That means that it’s a time we rely heavily on the municipal water system to tend to plants, in contrast with other times of year where rainfall can be sufficient. Salinity in the water supply means that this resource will be altered. Like many compounds, salt (Sodium Chloride) will ionize when dissolved in water. When sodium levels are high, the sodium will replace plant-food ions, like Potassium, Magnesium, and Calcium, thus interfering with nutrient absorption. Different plants will be affected to differing degrees. A few of the heavy-hitters found in New Orleans’ landscapes are classified as salt-sensitive. Keep a close eye on your Azaleas, Camellias, Roses, Gardenias, Crotons, and Boxwoods once salt water enters the municipal supply.
The beautiful but salt-sensitive Rhododendron indicum is native to Japan.
As gardeners who love to promote home food production, we’d be remiss not to bring up edibles. There are a lot of salt sensitive fruit trees and vegetables, but there is also plenty of resiliency to be found. LSU Ag Center has done a great job circulating this information, including in this article published on NOLA.com. For those of you who aren’t subscribers, they state that “the most salt sensitive vegetables include beans, onions, cucumbers, radishes, and celery.” So as you plan and plant your Fall gardens, keep this in mind and choose differently! Citrus trees are another key local crop that are sensitive to salt, and navigating this is a little complex. Salt concentrations will build up in soil over time as salty water is added to the biome and the water evaporates. This is especially true for plants in containers. Watering at night when evaporation rates are slower helps mitigate this effect, as does keeping moisture levels high and “flushing” the area with a non-salinated water supply.
It’s kind of hard to stomach that part of the answer we’re hearing is “water more” when the appearance of the wedge is directly tied to widespread drought throughout the Mississippi River watershed. While we value our citrus trees and our luxurious rose bushes, it certainly provides cause for reflection.
But all is not lost! There are plenty of coastal climate plants that have evolved some level of tolerance to salt water. Many of our favorite natives fall into this group: Persimmon Virginiana, Muhly Grass, Coreopsis, Blanket Flowers, Wax Myrtles, and more! We have long-loved the drought tolerance of these resilient growers, and this moment serves as reassurance that planting native is the way of the future. Species that have evolved in this climate are more equipped to handle these wild weather times. As we strive to increase the number of native plants in our own installations and work on establishing our own nursery of native species, we recognize the limited commercial availability of some of these plants. Check out the Native Plant Initiative for more information on the subject and a list of retailers in the area, so you can start adding these species to your gardens as well.
Another key adaptive strategy is to increase efforts of water storage. We are still in a subtropical climate, and we are still apt to get a significant amount of rainfall in any given year. Rainwater collection in the form of barrels is a great way to take advantage of plentiful times and redistribute the bounty throughout the drier moments of the year. In the midst of having this conversation with one of our clients, he brought up the cisterns that were commonplace in the New Orleans area in the past.
Vintage ad for cistern install/repair. Source: https://prcno.org/rise-fall-new-orleans-cistern/
In the 19th and early 20th centuries, New Orleanians actually relied on rainwater collection for their drinking water! The Preservation Resource Center of New Orleans published a fantastic article about the history of these cisterns in 2018, describing how they were banned in 1916 as information about mosquito-breeding and Yellow Fever began to surface. Today, Yellow Fever is not the public health threat it once was. We can also use closed-barrel system designs with fine-screen mesh to prevent mosquitoes from entering rainwater catchment systems. Beyond that, we have a plethora of mosquito-control techniques (both natural and chemical) at our disposal. To learn more about installing a sophisticated rainwater collection system, check out the California-based company Blue Barrel Systems. We are happy to offer our services (or just our tools and knowhow) on any rainwater collection project, so please don’t hesitate to reach out.
A Whimscapes-installed Blue Barrel System
There is something profound in the way this moment connects our past, present and future. It’s a nod to the nonlinear nature of progress and the importance of flexibility in times of difficulty. Letting go of things we think we need is always hard, and opting for a self-sustaining watering method can be more complicated than what we’re used to. But we’re here for the challenge– peruse the linked pages, ask the big questions, and come along.
