9 research outputs found
Emulation of a process-based estuarine hydrodynamic model
<p>Emulation modelling can be an effective alternative to traditional mechanistic approaches for complex environmental systems and, if carefully conceived, can offer significantly reduced run times and user expertise requirements. We present a case study of dynamic emulation for the domain of estuarine water quality modelling, by reporting the development and evaluation of a one-dimensional hydrodynamic model emulator. The proposed “neuroemulator” retains the dynamic nature of the process-based model utilizing a set of artificial neural networks. The underlying hydrodynamic model is routinely used for analysis and management of the northern reach of the San Francisco Bay-Delta estuary, a large complex region of strategic importance for water supply and ecosystem services on the Pacific coast of California, USA. The reduced computational expense of the emulator affords opportunities for direct use, as well as embedded use within other modelling frameworks such as those developed for reservoir operations and socio-hydrology.</p
Implications of Using On-Farm Flood Flow Capture To Recharge Groundwater and Mitigate Flood Risks Along the Kings River, CA
The agriculturally productive San
Joaquin Valley faces two severe
hydrologic issues: persistent groundwater overdraft and flooding risks.
Capturing flood flows for groundwater recharge could help address
both of these issues, yet flood flow frequency, duration, and magnitude
vary greatly as upstream reservoir releases are affected by snowpack,
precipitation type, reservoir volume, and flood risks. This variability
makes dedicated, engineered recharge approaches expensive. Our work
evaluates leveraging private farmlands in the Kings River Basin to
capture flood flows for direct and <i>in lieu</i> recharge,
calculates on-farm infiltration rates, assesses logistics, and considers
potential water quality issues. The Natural Resources Conservation
Service (NRCS) soil series suggested that a cementing layer would
hinder recharge. The standard practice of deep ripping fractured the
layer, resulting in infiltration rates averaging 2.5 in d<sup>–1</sup> (6 cm d<sup>–1</sup>) throughout the farm. Based on these
rates 10 acres are needed to infiltrate 1 cfs (100 m<sup>3</sup> h<sup>–1</sup>) of flood flows. Our conceptual model predicts that
salinity and nitrate pulses flush initially to the groundwater but
that groundwater quality improves in the long term due to pristine
flood flows low in salts or nitrate. Flood flow capture, when integrated
with irrigation, is more cost-effective than groundwater pumping
Projecting Water Withdrawal and Supply for Future Decades in the U.S. under Climate Change Scenarios
The sustainability of water resources in future decades
is likely
to be affected by increases in water demand due to population growth,
increases in power generation, and climate change. This study presents
water withdrawal projections in the United States (U.S.) in 2050 as
a result of projected population increases and power generation at
the county level as well as the availability of local renewable water
supplies. The growth scenario assumes the per capita water use rate
for municipal withdrawals to remain at 2005 levels and the water use
rates for new thermoelectric plants at levels in modern closed-loop
cooling systems. In projecting renewable water supply in future years,
median projected monthly precipitation and temperature by sixteen
climate models were used to derive available precipitation in 2050
(averaged over 2040–2059). Withdrawals and available precipitation
were compared to identify regions that use a large fraction of their
renewable local water supply. A water supply sustainability risk index
that takes into account additional attributes such as susceptibility
to drought, growth in water withdrawal, increased need for storage,
and groundwater use was developed to evaluate areas at greater risk.
Based on the ranking by the index, high risk areas can be assessed
in more mechanistic detail in future work
Projecting Water Withdrawal and Supply for Future Decades in the U.S. under Climate Change Scenarios
The sustainability of water resources in future decades
is likely
to be affected by increases in water demand due to population growth,
increases in power generation, and climate change. This study presents
water withdrawal projections in the United States (U.S.) in 2050 as
a result of projected population increases and power generation at
the county level as well as the availability of local renewable water
supplies. The growth scenario assumes the per capita water use rate
for municipal withdrawals to remain at 2005 levels and the water use
rates for new thermoelectric plants at levels in modern closed-loop
cooling systems. In projecting renewable water supply in future years,
median projected monthly precipitation and temperature by sixteen
climate models were used to derive available precipitation in 2050
(averaged over 2040–2059). Withdrawals and available precipitation
were compared to identify regions that use a large fraction of their
renewable local water supply. A water supply sustainability risk index
that takes into account additional attributes such as susceptibility
to drought, growth in water withdrawal, increased need for storage,
and groundwater use was developed to evaluate areas at greater risk.
Based on the ranking by the index, high risk areas can be assessed
in more mechanistic detail in future work
Projecting Water Withdrawal and Supply for Future Decades in the U.S. under Climate Change Scenarios
The sustainability of water resources in future decades
is likely
to be affected by increases in water demand due to population growth,
increases in power generation, and climate change. This study presents
water withdrawal projections in the United States (U.S.) in 2050 as
a result of projected population increases and power generation at
the county level as well as the availability of local renewable water
supplies. The growth scenario assumes the per capita water use rate
for municipal withdrawals to remain at 2005 levels and the water use
rates for new thermoelectric plants at levels in modern closed-loop
cooling systems. In projecting renewable water supply in future years,
median projected monthly precipitation and temperature by sixteen
climate models were used to derive available precipitation in 2050
(averaged over 2040–2059). Withdrawals and available precipitation
were compared to identify regions that use a large fraction of their
renewable local water supply. A water supply sustainability risk index
that takes into account additional attributes such as susceptibility
to drought, growth in water withdrawal, increased need for storage,
and groundwater use was developed to evaluate areas at greater risk.
Based on the ranking by the index, high risk areas can be assessed
in more mechanistic detail in future work
Projecting Water Withdrawal and Supply for Future Decades in the U.S. under Climate Change Scenarios
The sustainability of water resources in future decades
is likely
to be affected by increases in water demand due to population growth,
increases in power generation, and climate change. This study presents
water withdrawal projections in the United States (U.S.) in 2050 as
a result of projected population increases and power generation at
the county level as well as the availability of local renewable water
supplies. The growth scenario assumes the per capita water use rate
for municipal withdrawals to remain at 2005 levels and the water use
rates for new thermoelectric plants at levels in modern closed-loop
cooling systems. In projecting renewable water supply in future years,
median projected monthly precipitation and temperature by sixteen
climate models were used to derive available precipitation in 2050
(averaged over 2040–2059). Withdrawals and available precipitation
were compared to identify regions that use a large fraction of their
renewable local water supply. A water supply sustainability risk index
that takes into account additional attributes such as susceptibility
to drought, growth in water withdrawal, increased need for storage,
and groundwater use was developed to evaluate areas at greater risk.
Based on the ranking by the index, high risk areas can be assessed
in more mechanistic detail in future work
Projecting Water Withdrawal and Supply for Future Decades in the U.S. under Climate Change Scenarios
The sustainability of water resources in future decades
is likely
to be affected by increases in water demand due to population growth,
increases in power generation, and climate change. This study presents
water withdrawal projections in the United States (U.S.) in 2050 as
a result of projected population increases and power generation at
the county level as well as the availability of local renewable water
supplies. The growth scenario assumes the per capita water use rate
for municipal withdrawals to remain at 2005 levels and the water use
rates for new thermoelectric plants at levels in modern closed-loop
cooling systems. In projecting renewable water supply in future years,
median projected monthly precipitation and temperature by sixteen
climate models were used to derive available precipitation in 2050
(averaged over 2040–2059). Withdrawals and available precipitation
were compared to identify regions that use a large fraction of their
renewable local water supply. A water supply sustainability risk index
that takes into account additional attributes such as susceptibility
to drought, growth in water withdrawal, increased need for storage,
and groundwater use was developed to evaluate areas at greater risk.
Based on the ranking by the index, high risk areas can be assessed
in more mechanistic detail in future work
Projecting Water Withdrawal and Supply for Future Decades in the U.S. under Climate Change Scenarios
The sustainability of water resources in future decades
is likely
to be affected by increases in water demand due to population growth,
increases in power generation, and climate change. This study presents
water withdrawal projections in the United States (U.S.) in 2050 as
a result of projected population increases and power generation at
the county level as well as the availability of local renewable water
supplies. The growth scenario assumes the per capita water use rate
for municipal withdrawals to remain at 2005 levels and the water use
rates for new thermoelectric plants at levels in modern closed-loop
cooling systems. In projecting renewable water supply in future years,
median projected monthly precipitation and temperature by sixteen
climate models were used to derive available precipitation in 2050
(averaged over 2040–2059). Withdrawals and available precipitation
were compared to identify regions that use a large fraction of their
renewable local water supply. A water supply sustainability risk index
that takes into account additional attributes such as susceptibility
to drought, growth in water withdrawal, increased need for storage,
and groundwater use was developed to evaluate areas at greater risk.
Based on the ranking by the index, high risk areas can be assessed
in more mechanistic detail in future work
Projecting Water Withdrawal and Supply for Future Decades in the U.S. under Climate Change Scenarios
The sustainability of water resources in future decades
is likely
to be affected by increases in water demand due to population growth,
increases in power generation, and climate change. This study presents
water withdrawal projections in the United States (U.S.) in 2050 as
a result of projected population increases and power generation at
the county level as well as the availability of local renewable water
supplies. The growth scenario assumes the per capita water use rate
for municipal withdrawals to remain at 2005 levels and the water use
rates for new thermoelectric plants at levels in modern closed-loop
cooling systems. In projecting renewable water supply in future years,
median projected monthly precipitation and temperature by sixteen
climate models were used to derive available precipitation in 2050
(averaged over 2040–2059). Withdrawals and available precipitation
were compared to identify regions that use a large fraction of their
renewable local water supply. A water supply sustainability risk index
that takes into account additional attributes such as susceptibility
to drought, growth in water withdrawal, increased need for storage,
and groundwater use was developed to evaluate areas at greater risk.
Based on the ranking by the index, high risk areas can be assessed
in more mechanistic detail in future work