Geography Reference
In-Depth Information
data acquisition. The first, the Tenderfoot Creek study,
involves a well-established and self-organised catchment,
which requires standard hierarchical measurements that
exploit the natural organisation of the catchment. The second,
Chicken Creek artificial catchment in Germany, offers
unique challenges due to the fact it is an artificial catchment
rehabilitated after decades of mining activities, and it will
take some time to fully understand the dominant processes in
a fast changing landscape; it therefore offers unique chal-
lenges to the modeller. The third, in the Sel
Orkneys & Shetlands
ka Sora catch-
ment in Slovenia, is a forensic study aimed at understanding
the mechanisms that led to flooding, and highlights the
challenges in deciphering the mechanisms that led to
recorded floods on the basis of the markers left behind. Each
example represents the diversity of problems faced under
PUB, and the creativity that can be brought to bear on
addressing the learning and prediction challenges of PUB.
š
3.7.1 Understanding process controls on runoff
(Tenderfoot Creek, Montana, USA)
The case study describes a sequence of steps and infer-
ences that could be drawn about the Tenderfoot Creek
Experimental Forest (TCEF) headwater catchment located
in the Little Belt Mountains of Central Montana, USA,
utilising hierarchical data acquisition in the PUB context.
Each level of the hierarchy narrows the likely catchment
runoff behaviour to enhance PUB. The first step includes
inferences drawn from general hydrological understanding
of runoff behaviour in the context of the climate, biogeog-
raphy and physiography of the area. Second, inferences
about likely runoff behaviour can be drawn from nationally
or globally available data. Third, field visits further con-
strain possible behaviour with inference from simple field
observations.
Catchments in the Little Belt Mountains and similar
environments are characterised by shallow throughflow
runoff processes and variable source area hydrology and
are therefore likely to dominate TCEF hydrology because
of their physiographic setting, climate and likely weather
patterns. Shallow, permeable soils overlying less perme-
able or nearly impermeable bedrock lead to perched, tran-
sient water tables in the soil and weathered bedrock zone.
If deeper groundwater rise into the weathered bedrock/soil
zone is a significant mechanism, shallow throughflow can
still be a dominant runoff process because of the dramatic
increase in hydraulic conductivity above the bedrock zone.
Steep slopes and complex topography further promote
rapid throughflow above the soil
HOST Classes
1
12
23
24
25
26
27
28
29
98
99
2
13
3
14
4
15
5
16
6
17
7
18
8
19
9
20
10
21
11
22
Figure 3.11. Hydrology of Soil Types (HOST) classification system
for the UK at 1 km resolution. © NERC
CEH, © Cranfield
University and © The James Hutton Institute.
-
Earth's natural lakes in terms of area (Jacquot,
2009
).
Despite established recognition of the many critical envir-
onmental and social trade-offs associated with dams and
reservoirs, global data sets describing dam characteristics
and their geographical distribution are largely incomplete.
Figure 3.13
shows the distribution reported in the Global
Reservoir and Dam (GRanD) database of large dams
around the world along with their main purpose (Lehner
et al.,
2011
; Lehner and Döll,
2004
). According to the
GRanD database, about 34% of these large dams are
engaged in irrigation. GRanD data include (in most cases)
the dam and reservoir names, spatial coordinates, con-
struction year, surface area, storage capacity, dam height,
main purpose and elevation.
3.7 Illustrative examples of hierarchical data
acquisition
We end this chapter with a presentation of three different
examples involving PUB, each offering unique challenges to
predictions, and requiring different strategies for hierarchical
bedrock interface. Con-
vergence and divergence in the topography result in more
diffuse or more focused flow accumulation and influence
landscape scale runoff patterns, drainage rates and
resulting soil moisture distributions.
-
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