At Lava Lake, we are very focused on water availability, both for irrigation and for natural forage production. The more we study water, the more complex water becomes. Variables of interest include:
Phase:
Water or snow?
If snow, what is the temperature of the ground beneath? Percolation is impeded in the early spring if the ground is frozen; groundwater recharge is adversely affected; and the risk of erosive flows in stream channels is increased along with out-of-bank flooding. With less water in the top 8 – 12 inches of soil, perennials and, particularly, annuals may start the season well only to flag in time, resulting in less consumable forage and, in extreme cases, poor seed production, which likely negatively impacts annuals the next year as the in-soil seed bank is depleted.
What is the temporal temperature profile each spring? Two weeks of hot weather can send enormous quantities of snow-melt water down-system, plus suspended solids that adversely affect water quality and the native fishery. Heavy spring flows overwhelm the ability of our small in-stream reservoirs to capture the target percentage of such flows and the balance is “lost” — in our case, into the lava, to be expelled hundreds of years later from huge springs on the Snake River. You say, “Lost? Surely downstream use is important!” and I agree, but massive flows can overwhelm the downstream system as well in a typical stream and all of the water that rushes through is then not available for riparian vegetative growth or other natural processes for the remainder of the season.
Concentrating runoff in high peak flows can damage beaver dams, potentially mobilizing the sediments impounded behind these amazing structures and sending plumes of suspended solids downstream. Worse, the beneficial effects of soil building behind beaver dams — filling erosion channels and raising the water table, creating areas of natural sub-irrigation that extend further laterally from the stream course — can be undone in a season. This is particularly true in our landscape where beavers seem to come and go, sometimes with a few years intervening before recolonization. No engineers, no engineering marvels! Or at least no “emergency services” available from our energetic friends to repair a breached dam. If a beaver dam has been in place for a long time and a mature plant community has grown up on it and in and around the pond, a sudden de-watering spells doom. We’re left with a silty mess — at least until the system re-stabilizes.
Timing:
The timing of snowfall is much less important than the quantity (in liquid water-equivalent inches to normalize for moisture content). The timing of rainfall, however, is quite critical, particularly in the late spring and early summer. Everything is soggy in March and April from the winter snows; rain is less critical during this period. Rainfall in May and June — and, if we’re extremely lucky, July — is very important. Once the plant communities start to crank out biomass, we’d like to see them continue to do so. Only well-spaced rains of consequence assure this.
In the spirit that nothing is as simple as it seems (or, I sometimes think, should be!), I hasten to add that torrential rains (and associated winds) can also produce the adverse effects described above, can destroy crops, particularly barley (which we seldom grow but which is an important crop in our area) by beating it down or blowing it over when the seed heads are nearing maturity and alfalfa hay (certainly if mown hay is sufficiently drenched before baling). Spring rains (as opposed to summer thundershowers) are typically brought by storm systems. These storm systems are typically associated with cooler air. Cooler temperatures retard photosynthesis. The storms themselves of course involve clouds which diminish the incidence of solar photonic energy, thus also retarding photosynthesis and therefore plant growth and forage availability.
photo by Nancy Farese
A Good Year:
A great year involves an end-of-winter 120% snow pack, controlled melt with percolation and recharge, short periods (five to 10 days) of warmth interspersed among two-day light-to-moderate rains in the late spring and early summer (covering most of our operating area as opposed to thunderstorms which may drench a few square miles but leave surrounding areas parched).
This year, in contrast, we had an approximately 140% snowpack, a late spring, cold weather, many rains and a late start to plant growth which was followed, finally, by an epic, spectacular, I-hope-to-see-it-again-in-my-lifetime plant growth blitz that produced grasses more than five and six and seven feet tall across countless acres. And yet, our lamb weights were down slightly from last year. Why? Well, the forage wasn’t as well developed early in the season because of the cool temperatures and relative lack of sunlight and the moisture content of the myriad forbs — which are preferred by sheep — and the native grasses was higher than optimal, resulting in lower protein content as a percentage of wet forage weight. It’s also true that lambs in cold weather (when they’re typically smaller and rely more on mothers’ milk) spend a greater portion of their metabolic energy budget keeping warm and less on growing. At the other end of the spectrum, really hot weather causes lambs to “go off their feed” in the same way that you and I wouldn’t want to eat a huge pot roast when it’s 110 degrees outside. Plus hot weather brings gnats which lambs find irritating.
Risk:
Ah, risk! Water, if all goes well, promotes and maintains our healthy ecosystems. Lava Lake’s stocking density is set well below the sustainable level in a draught year. This year there is a fantastic surplus of consumable biomass. We leave it in place with a smile and a tip of the hat to Mother Nature. That biomass, however, drying now in the heart of summer, constitutes a real fire hazard come late August and September, two months that see scores of thunderstorms in South-Central Idaho. Well, thunderstorms mean lightning and lightning means fire. One thunderstorm can ignite several. And fires require fuel. This year, we have fuel in abundance.
The Real Deal:
I’m reminded of a comment my good friend Jim Bennetts made when we were discussing the water rights pertinent to an acquisition Lava Lake made many years ago. Jim, the king of sagebrush lawyers in my critical estimation and a man I greatly admire, sized up the water situation on the subject property and said to me, in his customary unhurried drawl, “Brian, you have excellent water rights. You just don’t have excellent water.” And you know, he was right! Believe me, I kept Jim’s words in mind as we expanded the operation over the next several years.
And On it Goes:
Water. Fire. Risk. A complex landscape with dramatic and unpredictable weather. Fascinating and occasionally terrifying. As every farmer knows, the crop isn’t harvested and delivered until it is.
Every year is different. We do something right. We misjudge. We learn something new. I wouldn’t give it up for the world!
photo by Glenn Oakley
