DISCUSSION: FIRE & FLOOD, Partners in Destruction
The purpose of this paper is not political in nature, but to explain the relationship between wildfires and floods. Mega-fires and heavy, large area precipitation are the focus of this work.
I am Allen Campbell and I have lived within the Gila National Forest for 78 years. My formal training is in Plant Ecology and Range Management. Our family has been volunteer weather observers for the National Weather Service since 1953 at the Gila Hotsprings, NM. I have witnessed the dynamic relationship between fire and flood regime shift over the years. It has been substantial to say the least! I hope this is received as intended, enlightening. Feedback accepted and welcome via email.
Wildfires are natural phenomena. Whether natural or human ignited, they have the same ultimate effect. A flood is a weather phenomenon—a rate of rain or snow-melt greater than the ground can absorb produces runoff. Both are subject to a myraid of edaphic, climatic, and biological conditions; i.e. Ecology, neither good or bad, and never political!
While both are major natural forces, and a necessary part of many ecosystems, when fire is followed by a flood, it often wreaks havoc on humans and ecosystems. Fire-enhanced flood is the term used by FEMA to explain this phenomenon.
Mitigating the havoc and accentuating the benefits of floods has long been an important human endeavor. This is because floods are the most expensive natural disaster. Dams, erosion control structures, and levies are solutions, but only if the money and the political will align.
Fire enhanced effect
The first issue is that floods have very little influence on the size and intensity of fires, but the size and intensity of fires have a direct correlation on the magnitude of destruction for rivers and the adjacent riparian ecosystems.
These ecosystems include man-made structures, such as irrigation ditches, irrigation diversions, cropland, recreational sites, access roads, utilities, and various buildings. Obviously, every one of the above is an integral part of our rural economic system.
The damage caused is not just from the volume of water, but also degraded water quality. This includes thousands of tons of silt that clog irrigation ditches and roadways. This silt, when dehydrated, assays up to 25% elemental carbon (ground-up charcoal). This first post-fire flood water is a soup of organic and inorganic fire residue, devoid of free oxygen and high pH. When a sample is taken of the flood water and flocculated, I have seen, after 24 hours of settling, 12% of the water column is mud.
This 'soup' exterminates every non-plant organism living in the stream, either by suffocation or lethal reaction to the extremely high PH. Water quality improves after the first flood, but the biota recovery takes many years. The recovery of vertebrate animals depends on the reproduction and migration, if possible, of isolated populations sheltered in unburned water courses. Endangered species are particularly vulnerable. In this case, survival may be so precarious that a few individuals survive only in isolated springs, and remain trapped there.
I have witnessed this in several places after the Whitewater and the Miller Fires. In four of those spring-fed refuges, the surviving fish succumbed to an extended drought.
The mechanism of fire-enhanced floods needs explaining. There are three main issues:
1. Heat from high-intensity fire drives off the combined water on soil particles, making the soil hydrophobic. Thus rain is shed, rather than being absorbed over the short time. (This is like putting drops of water on dry flour, it just balls up.)
2. The tree canopy intercepts the rain, and it simply evaporates there, or is absorbed by the leaves or needles. (an action common in conifers)
3. Duff, i.e. dead and rotting needles and leaves from the trees on the forest floor, which soaks up rain like a sponge. This water cannot move into the mineral soil because of the high capillary action of organic matter. Duff is well aerated and holds twice its dry-weight in water which will evaporate, contributing nothing to surface runoff.
The three above listed effects of wildfires greatly enhances runoff and the size of floods, for a given amount of rain. For example, in our Mixed Conifer forest, unburned and dry, that gets a three-inch heavy rain; the canopy and duff can easily absorb two or more inches of this rain, the remaining is easily absorbed by the mineral soil, and no runoff. Now, if the same area has been severely burned with the canopy and duff consumed, the three inches of rain hits the mineral soil which resists absorption. The results is then almost two gallons per square foot of runoff!
This extreme amount of runoff will lessen as the soil becomes less hydrophobic, but canopy and duff absorption require decades to regrow and redevelop to the point that existed pre-fire.
A history in Fire Policy in Southwest New Mexico.
Before I go any further, it must be said: Not all fires are destructive! An ignored campfire or a lightning-strike ignition does not develop into an inferno immediately. The rate of spread is determined by fuel, weather, and moisture levels, called the Haines Index. As this index rises, the spread is exponentially faster. Difficulty in containing the fire also grows exponentially, as well as the costs. Fire is simply a chemical reaction, following the laws of physics.
I do not believe there is any doubt that the recent number of very large wildfires in the Gila National Forest is unprecedented. It is partly caused by the US Forest Service's change in “fire policy.” The other causes are climate and the human effect, which are difficult to change. Lastly, weather and physics, which are impossible to change.
The policy of fighting fires quickly and aggressively came out of the Big Burn of 1910 in the Northern Rocky Mountains. By 1935 the policy became known as the Ten O’clock Policy which decreed that all fires should be suppressed by 10 am the day following its initial report. If not possible then 10 am the next day(s).
This policy was enforced when mounted (horseback) smoke chasers, rushed alone, to a fire that had been located for them, day or night. They had a very high rate of success if one cares to research their logs. The policy is not in effect today.
Today, a crew normally walks or drives to the reported fire, not delivered by aircraft if in a wilderness, and may not be equipped to suppress the fire. Sometimes, they simply monitor that fire, all of which start out like the birth of a baby, toothless and weak. Sometimes the fires just go out, it is too wet, the fuel too scattered, or just poor fire conditions. Often during the monitoring period the fire spreads slowly, still creeping along unchecked, and the perimeter is growing exponentially longer. At this point the watchers, even if they had the tools, couldn’t fire-line a small 5-acre fire before help arrives. If the wind comes up, they have wasted the opportunity to prevent a nightmare scenario.
Monitoring is fine, but fireline first if you are in the beginning or even in the middle of the fire season. To do otherwise, in plain text, is stupid.
It is often argued by Gila National Forest officials that the current problem is past aggressive suppression, resulting in high fuel loads in our forests. If that is really true, then the original Ten O’clock Policy needs to be followed on all classifications of USFS managed land, in droughty years. Then, with an equally aggressive Prescribed Burn Policy in wetter, non-fire season periods.
This is a common-sense approach, and is what the Gila NF is attempting to do, however unsuccessfully and very damaging. Unsuccessful because of legal and the self-imposed restrictions favored by the environmental lobby and Washington’s “one size all policy.” These are:
• No intentional ignition of prescribed fires in designated Wilderness.
• A “let burn policy” in Wilderness when the fire is natural caused, regardless of the season and climatic conditions.
• Choosing the “monitor option” if a fire is lightning-caused, or in an area far removed from human populations. Human-caused fires are more likely to be suppressed.
• Too dangerous to fight because: it is dark; the terrain is too steep; the crew timed out; add infinitum. Subjective reasoning subject to personal opinions.
The above is not a policy, it is a Gordian Knot.
Fire, the Second and Third Order effects
In the mega-fires that we have witnessed in the past 15 years, the First Order of effect is millions of acres of virgin timber, brushland, personal property and ecosystems consumed in a short period of time. And, of course, millions of tons of carbon dioxide entered into the atmosphere. This initial phase is extremely expensive regardless of tactic used, and the air-quality has human costs as well as discomfort.
The Second order is that of runoff, or Enhanced Flooding effect. It is persistent and will continue until the vegetation regenerates enough to allow a normal runoff regime to exist. This is a long term effect for those people, and ecological regimes, even outside of the burned area that are affected by the changed river flow and chemistry. The economic costs are very high, but non-linear.
The Third order effect is correctly called “Ecological regime shift,” the time necessary for full emergence of the “climax” ecosystem. For grassland and brushland this is fairly rapid. Grassland will recover sufficiently for grazing, from an economic point, in a season or two. Forests on the other hand, will require decades or even centuries before the timber has economic value, or the recreational value so desired by the general population.
The Real Costs of Forest Fires
We can ill-afford the enormous costs of even the First Order Effect on the National Treasury. Fire suppression costs us billions of dollars, Burn Area Restoration Efforts cost billions more. The affected communities, homeowners, ranchers, farmers, and businesses suffer greatly in direct costs and loss of income. Only a small amount of the private individual costs are offset by the County, State, or Federal governments. This offset is borne by all taxpayers.
Then there are the forest environmental costs. They are Americas biggest playground, and produce clean water, food, timber, a CO2 sponge, and a myriad of lesser items until they are burned to a crisp. Yes, they regenerate but in the meantime, we lose their bounty.
In fairness and accuracy, there are some environmental and economic advantages to wildfires that must be acknowledged.
Downstream of fires, runoff can increase, but the cost/benefit is not normally advantageous:
First, I recorded Mogollon Creek's gage readings after the Whitewater-Baldy fire of 2012, from 1994 to 2021. I then recorded the USGS's SNOTEL records for that drainage's precipitation, for the same 38-year period. I then selected the 5 years, pre-fire precipitation records, that closely matched each of the 5 post-year precipitation records. ( I focused on the December 1st to April 30th time frame) From the river gage records, for those dates, the post-fire gage readings were 229% of the pre-fire readings. This is a substantial increase of runoff! I will share the program and data to anyone that would like to see it.
Prescribed Fire is an important policy, and perhaps the best solution in practice. Most prescribed fires are completed successfully. However, they have escaped too frequently if conditions sharply deteriorate. Prescribed burns which escaped and became mega fires have had an enormous human impact in New Mexico.
How do we reverse the frequency of Mega-Fires?
I think this is a Forest Service management issue, They have a large cadre of well trained professionals who know what the problem is in the field. The main problem is the Gordian Knot of their current Fire Policy I alluded to above. Ultimately, it will require Congress to unsheathe its Sword of Legislature and cut the Knot. This is a political issue and needs legislation that will release fire science from the shackles of for-profit environmentalism. It will also require much more freedom in management at the local level because the Gila National Forest ecosystems is unique, as is every other National Forest.
Will the National Forest entity address this ever-increasing damage incurred to private land and businesses? Will our rivers continue to be sewer conduit, removing the muddy ash downstream, rather than flowing clear water to our farms and communities?
Yes, but only with the big stick from the citizens, delivered to Congress to take action.
Allen Campbell
Mimbres, NM