SESSION
07
ALIGNING LAND USE PLANNING
AND AGRICULTURAL PRACTICES
WITH RIVER RESTORATION
A li ti off QUAL2K ffor estim
Application
timation
ti th
the effect
ff t off shading
h di on
water
t temperature
t p t
regime
gi off smallll streams
t
iin agricultural
g i lt l
landsscape
p
Jan Kroulík ((Brno Universityy of Technology,
Technology
gy Czech Republic,
Republic
p
kro
oulik j@
oulik.j@fce.vutbr.cz),
j@fce vutbr cz)) Helena Králová ((Brno Universityy of Technology,
Technology
gy
Czech Republic)
I t d ti
Introduction
With the use of mathematical models and modern computer tools it has become an easy technique to studyy the dynamics of the river system. This paper describes and
demonstrates the application of the water quality model QUAL2K on small streams near Brno city (Czech Republic).
lic) On these small streams the long term research has been
f
focused
d on hydrogeomorphological
h d
h l i l degradation
d
d ti off stream
t
channel
h
l as wellll as hydrochemical,
h d h i l hydrobiological
h d bi l i l and
a d ecotoxicological
t i l i l properties
ti off water
t andd sediment.
di
t Since
Si
2008 continuous monitoringg of water temperature
p
has been carried out ((14 locations on Fig.
g 1),), usingg data loggers
gg s installed in selected pprofiles ((HOBO Water Temperature
p
Pro
v2 Data Logger).
Logger) Based on the evaluation of the monitored environmental factors,
factors the most suitable reaches for reestoration were proposed.
proposed
QUAL2K simulates a dynamic diel heat budget and water quality kinetics for a one-dimensional,
one dimensional steady-flow
steady flow systems.
systems It represents a modernized version of the QUAL2E
model. Numerical computations
p
are pprogrammed
g
in Fortran 90 and MS Excel is used as the ggraphical
p
user interfaace. All interface operations
p
are pprogrammed
g
in VBA.
The available data provide a good base for case study for relatively new water quality model. Temperature off water influences physical, chemical and biological in
in-stream
stream
processes The model was used to describe the effect of shading on small streams with engineered chaannel in the agricultural landscape,
processes.
landscape in some cases without
accompanying
i vegetation.
t ti Model
M d l assesses the
th effect
ff t off shading
h di (changed
( h
d during
d i potential
t ti l streams
t
restoration)
t ti ) on streams
t
t
temperature
t regime.
i
QUAL2K model
QUAL2K simulates a stream as a set of interconnected segments. Water quality constituent values are compputed for every segment which is defined as a stream reach
with point and nonpoint inflow sources and withdrawals that drive changes in water quality.
quality Each segment of thhe stream reach is modeled as having a trapezoidal channel
shape.
h
W t depth
Water
d th is
i calculated
l l t d from
f
steady
t d flow
fl in
i the
th segmentt using
i the
th Manning
M i equation.
ti
W t mass balances
Water
b l
are performed
f
d by
b QUAL2K for
f eachh segmentt to
t
determinee tthee ddischarge
dete
sc a ge longitudinally
o g tud a y tthroughout
oug out tthee st
stream
ea reach.
eac
QUAL2K cann simulate a number of constituents including temperature,
temperature
atmospheric
Headwater boundary
ppH, carbonaceouus biochemical demand, sediment oxygen
yg demand, dissolved
transfer
1
heat load
heat abstraction
oxygen organicc nitrogen,
oxygen,
nitrogen ammonia nitrogen,
nitrogen nitrite and nitrate nitrogens,
nitrogens
Point source
2
organic phosphoorus,
orus inorganic phosphorus,
phosphorus total nitrogen,
nitrogen total phosphorus,
phosphorus
Point abstraction
phytoplankton
h t l kt anndd bottom
b tt algae.
l
All these
th
components
t off the
th stream
t
can the
th
inflow
outflow
Point abstraction
3
i
software use to model and track changes in the longitudinal profile of the
dispersion
di
dispersion
i
4
Point source
stream causedd by changes in geomorphological conditions,
stream,
conditions flow rate,
rate
5
Non-point
sediment-water
di
t
t
riparian
i i vegetatio
t tion andd other
th factors,
f t
changed
h
d by
b stream
t
restoration.
t ti
abstraction
6
transfer
For the simulaation of water temperature, a heat balance approach is used
Non point
Non-point
7
source
sediment
for description off the sources and sinks of heat for each model segment.
segment The
h t fluxes
heat
fl
b t een water
betw
t andd the
th atmosphere
t
h include
i l d shorth t andd long-wave
l
Point source
8
solar radiation,, shadingg and cloud cover attenuation,, conduction,, wind
Downstream boundary
convection evapporation,
convection,
poration and condensation.
condensation The heat budget is calculated
Example QUAL2K segments describing a river
QUAL2K water
water-quality
quality fluxes for model
using
sing a diurnal
di rnal time scale.
scale Mixing
Mi ing of water
ater between
bet een adjacent segments is
reach
segments
ggh water movement from upstream
p
to downstream and
(source: QUAL2Kw theory and documentation) modeled throug
(source: QUAL2Kw theory and documentation)
dispersive mixing at segment boundaries.
boundaries Heat fluxes between water and
sediment are also included in QUAL2K.
QUAL2K
Prague
Brno
Fi 11: Monitored
Fig.
M it d locations
l ti
since
i
M h 2008.
March
2008
Experimental
As an example, the output from the model of small stream Leskava (Loc. 4 and 5, Fig. 2 and 3) is given, shoowing the temperature distribution in the longitudinal profile of
the stream before and after the restoration.
restoration Leskava stream springs in the small wooded area,
area it flows alternately through urban and agricultural landscape.
landscape Stream channel
h been
has
b
engineered,
i
d incl.
i l straightening
t i ht i in
i mostt off the
th river
i reaches.
h In
I Leskava
L k
stream
t
watershed
t h d (21,2
(21 2 km
k 2) fields
fi ld (42 %) andd development
d l
t (40 %) prevail.
il The
Th currentt
shadingg of the stream is within the current state model ((Fig.
g 6a)) considered in the range
g of 15-80%,, while withinn the model after ppotential stream improvement
p
through
g mere
extension of riparian vegetation (Fig.
(Fig 6b) shading is considered in the range of 60-80%.
60-80% Both models are based on
o the same atmospheric conditions,
conditions stream geomorphology,
geomorphology
etc difference is only in stream shading.
etc.,
shading
6 )
6a)
6 )
6b)
6 )
6c)
Di
Discusion,
i , Conclusion
C l i
Fig 2: Loc.
Fig.
Loc 5,
5 Leskava stream,
stream 3.
3 77. 2014
Fig. 6a-c:
Fi
6
QUAL2K model
d l output.
t t M
Models
d l off temperature
t
t
regime
i off Leskava
L k
stream,
t
June
J
1,
1 2014.
2014 Axe
A X:
X longitudinal
l
it di l profi
file
l off the
th stream
t
[k ] A
[km],
Axe Y:
Y water
t temperature
t
t
[°C]
[°C]. 66a: St
Stream
in current state, 6b: Stream after extension of riparian vegetation (change of shading), 6c: Combination of Fig.6a and Fig. 6b.
6 Percentage values indicate shading of stream.
Conclusion
Water
W
t temperature
t
t influences
i fl
physical,
h i l chemical
h i l andd biological
bi l i l in-stream
i t
processes. Many
M
f t like
factors
lik solubility
l bilit off gases,
g
viscosity,
i
it density
d it andd other
th properties
ti off water
t depend
d
d on
water temperature.
p
These factors influence all biological
g pprocesses, such as nutrient cycling
y g and decomposition
p
pprocesses, includingg life cycles
y
of organisms.
g
Excessive water temperature
p
reduces the solubility of oxygen and accelerates the process of bacterial decomposition, which can create conditions lim
miting the survival of some organisms in organically contaminated
streams High water temperature is a serious problem of streams with engineered channels.
streams.
channels One of the effects of stream restoration
r
is decrease of its water temperature.
temperature
Th results
The
lt in
i Fig.
Fi 6a-c
6 representt modeling
d li off temperature
t
t
regime
i off a smallll stream
t
i agricultural
in
i lt l landscape.
l d
O thi
On
this
stream the effect of shading was evaluated comparing situation before and after extension of riparian vegetation. The moodel
is designed
g
for a typical
yp
summer day.
y Duringg other seasons the effect of riparian
p
vegetation
g
on stream temperature
p
willl be
lower QUAL2K,
lower.
QUAL2K of course,
course allows to model many others components,
components such as pH,
pH carbonaceous biochemical demaand
and,
sediment oxygen demand,
demand dissolved oxygen,
oxygen nitrogen,
nitrogen phosphorus and others.
others These models can be used to display the
currentt state
t t off these
th
components
t in
i the
th stream
t
l it di l profile
longitudinal
fil by
b insertion
i
ti geomorphological,
h l i l hydrological
h d l i l andd
meteorological data into the QUAL2K software and subsequent model calibration. Another option is to use the softwaree for
modelingg current state changes
g of a stream,, e.g.
g either duringg the river restoration pproject
j design
g or after,, before the pprooject
j
Fi 5:
Fig.
5 HOBO Water
W t Temperature
T
t
Pro
P v22 Data
D t Logger,
L
implementation.
implementation
Optical Interface for data transfer
This application of the QUAL2K software proved,
proved that stream simulation or modelling is a common cost-effective
cost effective wayy for (source: http://www.onsetcomp.com)
water
t quality
lit monitoring
it i andd predicting
di ti the
th future
f t quality
lit off rivers
i
andd streams.
t
Fig. 3: Loc. 5, Leskava stream, 3. 7. 2014
Fig. 4: Loc. 11, Bobrava stream, 3. 7. 2017, Logger
A k
Acknowledgements:
l d
t This
Thi researchh was fifinancially
i ll supported
t d bby th
the Mi
Ministry
i t off Ed
Education,
ti Y
Youth
th andd S
Sports
t off th
the C
Czechh R
Republic,
bli grantt no. FAST
FAST-J-14-2415.
J 14 2415