Part I: Wai
It used to be thought that life on earth required two elements: sunlight and water to flourish. Luckily for us, our planet is referred to as a “Goldie Locks” planet, orbiting at the correct distance to receive enough solar energy to keep water liquid, while still providing enough warmth for terrestrial life and radiation for photosynthesis. However, with the discovery of hydrothermal vent communities and chemotrophs that can metabolize molten ions at the bottom of the sea, society has now revised its hypothesis of how life started on earth from involving two elements to just one key: water.
Water makes up 75% of the earths surface and 75% of our body mass. Is there any wonder it is sacred to indigenous populations? In New Zealand, (and Spanish Colonial California), territories were denoted by environmental markers, including watershed boundaries. Though watersheds do not provide straight, surveyable lines, they divided the landscape into ecologically-relevant parcels. All precipitation that falls into a certain watershed will eventually make its way into its namesake river (e.g. Waikato), and out to sea. Generally, watershed boundaries are peaks of mountains or hills and thus the owner of the land controls management from the down-river lowlands to the mountains the cap the headwall of that river’s tributaries. By dividing land on an ecological basis, one land manager (or Iwi in the case of classical New Zealand culture) can oversee all the activities that will impact water quantity and quality, necessary parameters of a sustainable society.
Up until British colonization of New Zealand, Maori Iwi had divided both island into watershed-based territories to ensure yearly supplies of water, crops, birds, and fish to eat. Yet, the British survey system soon broke the islands up into straight-lined, parcels of land, disregarding the natural flow patterns of water. Though this system provided private land for settlers, it resulted in competition for water and a disconnect between the various stakeholders along the river. According to the 1840 Treaty of Waitangi, Iwi were supposed to receive jurisdiction over all the freshwater in New Zealand in exchange for bowing to the British Crown but now, nearly two centuries later, watersheds are broken, and “clean green” New Zealand is starting to experience the same water quantity and quality issues that are being felt the word over.
Part II: Crisis
The global hydrologic cycle is under attack! In the last century, industrial development has prompted nations to build mega-dams for flood control and hydroelectric power, divert and channelize streams to irrigate agriculture, and even overdraw from slow-to-fill groundwater sources.
In California alone, hundreds of dams block the movement of sediment and fishes on nearly every major river system in the state, and all the while agricultural (70+% of all water allocations), industrial, and municipal users continue to expect more water to keep up with an economic system that hinges on constant expansion.
The Canterbury Plains of New Zealand’s South Island already creates seventy percent of NZ’s irrigated water demand, and intensive agriculture continues to expand! The biggest city in these plains, before the 2010/2011 earthquakes, Christchurch was one of the largest cities on earth to still get its water from unfiltered groundwater. But, even if the quakes hadn’t damaged the piping system, nitrogenous waste and sediment from upstream dairying and agriculture was already infiltrating the basin, creating a need to begin filtering the water within the next few decades.
Water moves through groundwater very slowly, but it seems humanity is even slower to move. Recent leaps in water efficiency technology can greatly reduce the water that farmers and homeowners “need” while maintaining similar yields. Unfortunately, “prohibitive infrastructural costs” and subsidized water prices (users still don’t pay for water in Canterbury) create no economic incentives for users to change the status quo. Luckily, as hydrologic science has improved its metrics, the New Zealand government has stepped in to regulate gaps in management. Resource Districts in NZ were formed along major watershed boundaries to align management regimes with ecological barriers. In 2012, the Canterbury Region outlawed cattle grazing directly on the streambanks to reduce soil erosion, stream sedimentation, and nitrogenous waste leaching. Also in 2012, it was mandated that farmers measure water withdrawals from wells and stock races (irrigation channels).
All of the above measures improve accountability in water use and promote local adaptation but are they enough? As measurement technology improves, new pollutant cycles are found and “safe” concentrations are discovered to be unsafe. Some of the first giant dams like the Shasta Dam in northern California are being considered for removal due to ecological impacts but at the same time developing nations are receiving bonds from the World Bank and international investors to build newer mega-dams, often displacing indigenous populations and cultures permanently. Synergies between water development schemes are considered within a single nation or region, but globally projects are being completed largely independent of each other.
The hydrologic cycle, in contrast, is a global phenomenon and linked to almost every nutrient cycle we know of. Take for instance the global silica cycle:
Silica is exposed and released through weathering in the mountains and flows through streams to the ocean. In warm bays and shallow oceans, diatoms and other phytoplankton use silica to form protective cases and once those plankton die, that silica sinks to the bottom of the sea where it will take millions of years before it can be uplifted in the formation of some new mountains. Phytoplankton are photosynthetic and the major source of carbon sequestration/oxygen production on Earth. As my NZ water professor postulated, blocking sediment by damming all the major rivers on the planet could slow or even halt ocean photosynthesis with dire consequences for terrestrial and marine life.
Many Californians are already well aware of the fact that our human manipulation of the hydrologic cycle was over-engineered and under-informed but it seems that many other places will make the same mistakes before humanity will reconsider its place in the global water system.