216
technologies, improvements in power plant cooling technologies, and advances in
industrial wastewater recycling. Also, it is important to note that some withdrawals
are a poor proxy for water use; much of the water withdrawn for agricultural use is
consumptive, whereas much of that withdrawn for power plant cooling is not.
Water quantity law is state law and varies considerably among states. Those with abundant fresh water tend to have less regimented systems governing water rights, while those
with more limited supplies tend to have elaborate water rights regimes. Two predominant
models have shaped state water quantity law: riparian rights and prior appropriation rights,
although over time many states have adopted modifications and combinations of the two.
A pure riparian rights doctrine grants use rights in water to landowners whose property abuts a water body such as a river or a lake. In times of shortage, all users participate
in reducing use. This doctrine originated in England and was transplanted to the USA
where the "reasonable use" overlay, sometimes called the "American Rule" was established, restricting riparian users from making unreasonable use of the water.
“Reasonable use” is, of course, a slippery term, and the determination of reasonable use is multifaceted. It includes consideration of the suitability of the water body
for a particular use, such as drinking water, irrigation, fish propagation, or navigation, along with the social and economic values of that use, and the extent to which
that use causes harm to others.
The appropriative rights doctrine was introduced in the arider western states
where cultivating crops required regular irrigation. One who diverts water from a
stream and puts that water to beneficial use establishes a water use right. The right
is usually limited in scope by purpose (e.g., irrigation of a precise number of acres),
the total amount of water or flow rate, and sometimes by the time of year.
Priority in time trumps proximity in space; an established right is protected
against any other user who might assert the use of the water at some later time.
Water rights with earlier appropriation dates are more valuable than rights with later
dates, because in times of shortage, later (more “junior”) appropriations are curtailed
first. Early (“senior”) water rights, particularly non-consumptive water rights for
hydroelectric plants, can have significant impacts on downstream users. For
example, the 1902 water right for the relatively small (15MW) Shoshone power
plant on the upper Colorado River creates substantial, reliable downstream flows,
protecting rights of municipal and agricultural users lower on the river.
Watersheds frequently span two or more states, creating the need for interstate compacts or other instruments governing water sharing. These agreements usually focus on
three areas: water apportionment, pollution control, and flood control (see Chap. 19).
5
For example, the Mississippi River watershed, one of the largest in the world,
drains about 40% of the land mass in the continental USA and includes 31 states and
two Canadian provinces. Therefore, the watershed is impacted by the laws and regulations of all 33 state/provincial jurisdictions and two national governments. In addition, the Mississippi is subject to two basin-specific interstate compacts governing
water pollution: The Louisiana-Mississippi Tangipahoa River Waterway Compact
and the Mississippi River Interstate Pollution Phase-out Compact.
5 An exception to the three focal areas noted above is the Atlantic Salmon Compact of 1983
(Public Law 98-138) which focuses on restoration of the Atlantic salmon fishery in the
Connecticut River Basin.
B. Kinne and D. Magee
technologies, improvements in power plant cooling technologies, and advances in
industrial wastewater recycling. Also, it is important to note that some withdrawals
are a poor proxy for water use; much of the water withdrawn for agricultural use is
consumptive, whereas much of that withdrawn for power plant cooling is not.
Water quantity law is state law and varies considerably among states. Those with abundant fresh water tend to have less regimented systems governing water rights, while those
with more limited supplies tend to have elaborate water rights regimes. Two predominant
models have shaped state water quantity law: riparian rights and prior appropriation rights,
although over time many states have adopted modifications and combinations of the two.
A pure riparian rights doctrine grants use rights in water to landowners whose property abuts a water body such as a river or a lake. In times of shortage, all users participate
in reducing use. This doctrine originated in England and was transplanted to the USA
where the "reasonable use" overlay, sometimes called the "American Rule" was established, restricting riparian users from making unreasonable use of the water.
“Reasonable use” is, of course, a slippery term, and the determination of reasonable use is multifaceted. It includes consideration of the suitability of the water body
for a particular use, such as drinking water, irrigation, fish propagation, or navigation, along with the social and economic values of that use, and the extent to which
that use causes harm to others.
The appropriative rights doctrine was introduced in the arider western states
where cultivating crops required regular irrigation. One who diverts water from a
stream and puts that water to beneficial use establishes a water use right. The right
is usually limited in scope by purpose (e.g., irrigation of a precise number of acres),
the total amount of water or flow rate, and sometimes by the time of year.
Priority in time trumps proximity in space; an established right is protected
against any other user who might assert the use of the water at some later time.
Water rights with earlier appropriation dates are more valuable than rights with later
dates, because in times of shortage, later (more “junior”) appropriations are curtailed
first. Early (“senior”) water rights, particularly non-consumptive water rights for
hydroelectric plants, can have significant impacts on downstream users. For
example, the 1902 water right for the relatively small (15MW) Shoshone power
plant on the upper Colorado River creates substantial, reliable downstream flows,
protecting rights of municipal and agricultural users lower on the river.
Watersheds frequently span two or more states, creating the need for interstate compacts or other instruments governing water sharing. These agreements usually focus on
three areas: water apportionment, pollution control, and flood control (see Chap. 19).
5
For example, the Mississippi River watershed, one of the largest in the world,
drains about 40% of the land mass in the continental USA and includes 31 states and
two Canadian provinces. Therefore, the watershed is impacted by the laws and regulations of all 33 state/provincial jurisdictions and two national governments. In addition, the Mississippi is subject to two basin-specific interstate compacts governing
water pollution: The Louisiana-Mississippi Tangipahoa River Waterway Compact
and the Mississippi River Interstate Pollution Phase-out Compact.
5 An exception to the three focal areas noted above is the Atlantic Salmon Compact of 1983
(Public Law 98-138) which focuses on restoration of the Atlantic salmon fishery in the
Connecticut River Basin.
B. Kinne and D. Magee