Lecture Notes:
Oct. 7
Wrap-up Water Resources
Water resources raise a couple of key issues with human use of natural
resources:
·
allocation
and
·
estimating supplies, especially
problematic with variable resources like water or hard-to-measure resources like
soils.
Soil is typically “allocated” along with the market for private property:
you own land then you own the soil and can use it as you see fit for your
benefit. Farmers use the soils on their farms. Water, on the other hand, is
more fluid, flows across the land, is on you property for a while, then on
someone else’s. So, we have developed
more legal and policy (non-market) mechanisms for allocating water.
The textbook touches on water resources very broadly, so this is our chance to particularize this course to the region in which you now live: The American West. In much of the West water is limited by climate, so water users have developed elaborate systems to gather, store and transport it. Storage in large reservoirs is needed because most western water comes from snowmelt in the spring, but use is year round. Thus, the spring melt must be stored so that it can be used the rest of the year. The largest use is for irrigation, comprising 80% or more of all western water use. The rest is used in what water planners call municipal and industrial (or “M&I”) applications. The key municipal use is “domestic” or household water, used for everything from washing dishes to watering the yard. Landscape watering is a big part of this, and is “consumptive,” (whereas many household uses are non-consumptive and return almost the same amount of water to streams and rivers thru the wastewater system). Thus lawn watering is a main area where planners look for conservation and efficiency in municipal use.
We’ll spend
our time on the social institutions by which western water is allocated, and
talk about the complicated allocation of water in the Colorado River. Boulder
is technically in the South Platte drainage, but we do use some Colorado River
water brought through a tunnel drilled under the continental divide, so this is
a local as well as a regional issue.
Here are the
points that will be discussed in class:
1. Users'
"legal rights" to water are defined in the US by two systems: (A) riparian rights which allow use of
water by landowners adjacent to the stream or water body; and (B) appropriative rights which guarantees
the "first appropriator"---the first person to make "beneficial
use" of water---the right to continue taking a fixed amount from a stream
or other water body. Riparian rights only work logically in the wetter East,
while appropriative rights were developed in the drier West.
2. Western
water law thus allows the "appropriator" to extract water from a
stream and to move it to a place of use. They have a right to the water as long
as they put it to a "beneficial use." Water courts and other
institutions (e.g., water "masters" hired by rights holders in a
basin to police use) establish rules and enforce use rights. One of those rules
has been that rights holders can lose their water right if they do not use it
over some period of time. This is why many analysts claim that western water
law tends to work against conservation---if a user conserves water, or
simply leave their share in a stream, it can be apportioned to another who will
use it.
Western water
issues are complex and technically complicated, so we won't go into much
detail. But it is important to note a few major issues.
3. One aspect
of appropriative rights is that it tends to encourage water taken out of
streams and not necessarily returned, so many western streams and rivers are
dried up (or "de-watered") by users. This, of course, damages stream
ecology.
4. Sometimes
something more than simple water rights are needed, as in the case of
interstate rivers and international rivers (the Colorado is both). The Colorado
River is heavily appropriated, such that some form of inter-state agreement was
necessary to provide a framework for the individual water rights holders in
each state. The Colorado River Compact was signed in 1922, with CO, UT, WY, and
NM in the "Upper Basin" and AZ, NV, and CA in the "Lower
Basin." The compact assumed the average annual flow of 16.4 million ace
feet (MAF) with 7.5 MAF given to the Lower Basin (one of which had to come from
tributaries entering below the upper/lower gage point at Lee's ferry) states
plus 1.5 MAF to Mexico through an international treaty. This means that the
Upper Basin got 7.5. The lower basin states also get to use any surplus the
Upper state do not use, as long as Mexico gets its share.
8. But these
amounts do not come down in dry years, and there is paleo-climatological
evidence that the long-term average flow is more like 13.5 MAF instead of
16.4! So, one could say that in a
normal year the river is still over-appropriated. Until recently, as the West
has grown in population, this was not a problem because not all states were not
taking their share under the compact. In fact, the upper basin states, like CO,
were not suing all their water so lower basin states like California actually
could use more than their compact amounts.
Several dry
years, and growth of the upper basin states now means that the river is on the
verge of total depletion, and there is growing pressure to re-negotiate the
compact.