Redwood Reader

I am trying to find the answer to retaining water in a watershed, or at least extending the legnth of time between last precipitation and the date the creek dries up in August. I average over a hundred inches of rain a year, the watershed is only about three and a half miles long and a little over a mile wide. It sits atop the Triple Junction of the North American, Gorda and Pacific plates and has its own fault on the geology maps. The more I studied the water situation and tried to apply proposals, the more obvious it became we were missing some method nature uses to do this.
Many days on Waterforum and Agroforestry newsgroups led to some key points:
Watersheds retain water through forests
Complete forests include trees, duff, roots, fungi and soil
Complete forest carbon budgets must include the 25 or more percent of annual production stored underground
Complete forests rarely slide even in extreme events
Second growth forests feel much drier than old growth
Thousands of species of fungi inhabit wet forest, most synbiotic with the trees as mycorhizzia
Mycorhizzial fungi are ubiquitous in vegetated areas
The few exceptions are pioneers or annual grasses and forbs that reseed annually to offset climatic conditions. Invasive plants are often of this type and need no mycorhizzial associates, and often create dense colonies that soutcompete slower growing native perrenials.
Mycorhizzia infect millions of root hairs, simultaneously, redundantly, in succession and every other combination. The same piece of ground will be reinfected over and over, each time adding a drop or two of glomalin adding to the water storage capacity drop by drop, millions of times a day.
Soil carbon is found far below the duff layer and far from roots
Best restoration tool is tree planting
Most cost effective method is leaving it alone
Canopy and duff slow precipitation so it will sink into the soil
Rising carbon dioxide levels stimulate plant growth above ground, double in the root mass and increase stored carbon five fold
No till methods preserve soil carbon and build the soil up
Aanerobic decomposition forms methane
Greenery is advancing north and moving up the mountains
The Great Basin has lost its grazing value by losing the perrenial sage to the annual cheatgrass
Fires are frequent and seem to be getting worse
Glomalin is a soil glue, produced by mycorhizzial fungi, a structural part created by many species to perform specific function of stregnthening the hyphae walls when it must cross pore spaces in the soil
Glomalin was discovered in a single crop environment at USDA SAR in 1996 with vaso arbuscular mycorhizzia
Forest trees are ectomycorhizzial but the sticky stuff is caonfirmed by mycology professors relating to a poster
Loose sediment is the only problem in the experimental watershed
All the pools are filled in and the banks scoured.
Less and less rain is required to cause the creek to jump its banks
High rainfall scours the banks and takes all our and natures successes to that point, downstream
19 springs before the fire are reduced to four
Drilled wells are far below the level of my stream. Aquifers are too deep to be responsible for low flows.
Theres a bunch of other interesting tidbits to go on but there is no pattern here, no answer to urban sprawl or why vast landscapes are dehydrating, or the cause of sedimentation or what is happening when it is working right. Until we get to glomalin. Like magic we can see the opportunity cost of glomalin destruction and the true devil in the details of development of many kinds. We gat to generalize in a way big enough to legislate and change curriculums. There is a lot to learn but the topic is so big everybody can contribute.
Accepting that glomalin is as ubiquitous as mycorhizzia in general, and that mycorhizzia expand along with tree roots, we can see:
All parts of the green landscape absorb some water but will reach saturation at some point
All pats of the grren landscape are producing glomalin
Saturated landscapes will move downhill toward the creek
Glomalin storage will be in proportion to the type of vegetation and the time between disturbances
GLomalin gives the soil porosity, which will vary by region, soil type and species.
Glomalin is tough, durable, long lived but not inorganic and ultimately breaks down
The longer left alone the more glomalin saturated the soil becomes, increeasing its water holding capacity
Human activity on the land can be seen as a percentage of glomalin system impacts, rating each activity in the amount of water it can hold compared to some number it could hold under maximum glomalin production conditions.
In descending order of available absorption we find old growth forests at 100%, savanna, grasslands, farms, lawns, down to pavement and roofing, 0%
The watershed thus is measured in three directions with its capacity being total soil volume in the glomalin producing zone, multiplied by porosity
The difference will be in how large a rain event it takes to overwhelm the system
Glomalin loses its magic propertis when exposed to sunlight, air or running water, reverting to CO2 and fine sediment
FIne sediment moves through the watershed as dust or mud in running water, collecting in the stream bottom cementing rocks into solid impenetrable masses
Now insights and ideas come flooding like the waters from a breached dam. It is significant this dam is about flooding rather than hydro or irrigation, because flooding is caused by poor watershed health and poor planning in the flood plain areas. There are many stump ponds back East that were built for mills before electricity. Most were floodoed after the trees were felled with an axe, and should have glomalin buried in their sediments. This would be a really intersting subject, just one of thousands we would need to move this concept into the hard numbers of engineering. Nevertheless, rules of thumb have been amazingly accurate for a long long time.
Forest floor damage creates huge amounts of sediment.
Dust is a problem in the creek.
Clearcutting exposes the system to additional damage through exposure of the soil to trhe elements after the binding properties of glomalin are compromised.
Of course native plants thrive with their natural associates.
Desertification is avoidable.
Sustainable agriculture, like modern dairy farming or the old orchard-pasture method find levels of sustainability without being aware of glomalin but we can see advantages now, compared to say bare floor orcharding or treeless pasture.
Creeks live on water stored in the root zone, Aqqifers are recharged by excess water filtering through these zones due to gravity
Fossil fuels are as likely to be buried glomalin deposits as aboveground material. In fact, undisturbed for millions of years, there should have been a lot of soil stored carbon when inland seas flooded, or other major flooding events.
Anerobic decomposition of glomalin will probably yield methane in decades, not eons
The opportunity cost for water storage in a dam site becomes the acreage flooded times the maximum porosity and volume, plus the reduced capacity of cleared land whether completely lost to paving or impaired by vegetative treatment, plus capacity lost to disrupted drainages, plus lost terrestial riparian systems and fisheries, plus the amount evaporating off the reservoir each year rather than stored safely in ther ground available to terrestial life.
Glomalin destruction cuts sediment loose, the number one problem in many dam systems.
Greater damage is likely from further development in the watershed above the dam.
Much of this dqamage already exissts and is exacerbated by dam building. Flooding is a sure sign upper watershed health is not all it should be.
The old soil science thing of drying soil and weighing it do not help as we cannot separate the eveporated water from the gasified glomalin reverted to CO2. Neither are the particle filters as helpful as they seemed.
Opportunity cost in terms of carbon would include lost glomalin production, lost glomalin and water storage capacity, lost carbon dioxide sequestration, flooding and landscape instability, carbon loss to ground disturbance in the construction areas outside the dam proper, co2 conversion to methane in anerobic digestion of glomalin in flooded areas.
In the West many small dams had timber cut around them to increase runoff and hold it in the reservoirs until later in the year. When the chapparal grew up the water table seemed to return. When forest came back the water table seemed to lower, so they cut the trees again. Now we can see the error. The soil is biologically conditioned to store water. The water table thus moves as a result of glomalin, its capacity growing at depth and in radius from the plant and in response to that plants function, as pioneer or main player, in the landscape.
The opportunity costs to not build the dam include less flooding from greater surface area of absorption and deeper storage capacity, less surface disruption outside the dam preventing more glomalin loss, lower fire risk, healthier forests and vegetation, less sediment, more and better fisheries and wildlife habitat, no changed environmental variables making inhospitable conditions for native species, cleaner rivers, more upslope surface waters such as seeps and springs, more carbon sequestered, no methane conversion from drowned CO2, and many times preservation of archeological sites often on the benches above rivers.