Acta Agrophysica, 2002, 68, 109-113
EMPIRIC VERIPICATION OP THE "SWATREZ" MODEL UNDER CONDITIONS AT THE "HAJDÓW'
EXPERJMENTAL RESEARCH STA nON D. Kowalski.
r
Wiśniewski, H. WróbelLublin Technical University, Nadbystrzycka 40 str., 20·618 Lublin, Poland
A b s t r a c I. This article presellls the initial resulls ol' field research conducted allhc "Hajdów" cxperimclltal research stalion near Lublin.
Mensurements show groundwater levels ovc;- a I month period. compared wilh Ihe cakulation results obtained hy the "SWATREZ simulation model ovcr thc same period.
K e y \V o r d s: 50;1 physics. watcr 1l1Clvcmenl simulation
INTRODUCTION
One of Ihe methods for Ihe prognosis or soil mois!ure condilions is Ihe use of malhemalical models. The simulation of phenomena occurring in a so il-plant-almos-phere syslem makes it possible to eSlimate the work of any improvement syslems from the design slage alone, Ol' as in Ihis case, after the failure ofthe investment.
Many models can be used lo improve design, bul verificalion is slill unsalis-factory. The "SWATREZ modei was verified by Brandyk among olhers [I].
The present paper, allhough smali in scope, continues verification oflhe work.
OBJECT OF Tł-IE RESEARCH
The "Hajdów" experimenlal research slation is situated near the City of Lublin in Ihe Bystrzyca River valley. The system ol' wasle waler purification integraled wilh the irrigation of industrial crops [3] was tested here. The melioration system installed together with stable moislure condilions played an important role. The re-search was conducted over 21 separate fields wilh various drainage system and
110 D. KOWALSKI eI al.
plants. For the purposes of this paper, only four of them we re chosen - fields 6A,
6B, 7 A and 7B, where grass was under eultivation. The drainage parameters are as follows: spaeing 20 m, diameter 50 mm, deep 1.1 m (for field 6) and 1.5 (for field 7). The letter "A" signifies that this field was not irrigated. The letter "B" - that
the fields were irrigated by waste water from the "Hajdów" treatment plant. Soil at the "Hajdów station is organie in origin, mainly peat. The detailed soi! parameterisation (pF eurve, water eonduetivity ete.) was done based on arehive data for MtI be soil, reeeived from the Lublin Institute of Land Reclamation and Grassland Farming. Using referenee data in plaee of field experiments has a major
bearing on the quality ofthe simulation results reeeived.
Unfortunately, during the simulation work, the authors were not in possession
ofthe results ofthese experiments.
Additionally, in the simulation proeess, the authors had used meteorologieal
data, from the meteorologieal station installed at the experimental researeh station (temperature, rain, humidity, wind) and from the Lublin-Radawiec station (insulation).
The experimental object was equipped with net of observation wells and pie-zometers. The speeifies of the mathematical model presented in this artiele, only
need verifieation of the researeh wells in the middle of the drainage.
Measure-ments indicate the levels ofthe groundwater table, taken daily at 9 a.m., during the
1 st. month - May 1997.
SIMULArION MODEL
For moisture eonditions and groundwater level simulation in seleeted soil pro-files, the authors ehose the "SWATREZ" model - as elaborated by Feddes, Kowalik and Zaradny [2] based on the Riehard equation with source faetor:
eJh =
_
I
_~[
k(h)(i)h
+
I
)]
_
S(h)at
C(h) cJx eJz C(h) (I )where: " - soi! water potential, t - time, C(h) - differential water eapacity, K(h)
-water eonductivity, z - vertieal eo-ordinate, S(h) souree faetor (transpiration etc.).
A description of the entire model is ineluded in the Feddes, Kowalik and Zaradny work [2]. Using this modelmakes it possible to simulate moisture change dynamics in the soi! profile when considering parameters of the soil, the plants,
AN EMPIRIC VERIFICATION OF TI·IE "SWATREZ" MODEL 111
SIMULATION RESULTS
Figure 1 presents the ground water level obtained by simulation calculations and their comparison with measurement data. As can be seen, in spite of the
inac-curate input of essential data (i.e., soil parameters), the calculation results are very
similar to the measurement data. During the measurement period - on lhe 15th and
16th day - a failure ofthe irrigation system occurred. There was uncontrolled
irri-galion of field HA" by breaches in the dykes in field ·'B". Thus a correct estimation
of irrigation amounts was impossible.
In order to better present the verification ofthe simulation results, the authors
made a few minor statistical calculations, and minimised the standard error:
and average deviation:
s=.!.
n i i 2 "i,("meas - "calc) n i=1 I 11I
.
.
I
a
= -L
h:
lIeas - h~a/c 11 i=1 (2) (3) i iwhere:
h meas
- measured groundwater level,h
cale - groundwater level calculatedby simulation model, 11 - num ber of observations.
The results ofthe calculation are collected in Table I.
T :1 b ł c l. The standard error and average deviation, as measured and ca1culated by the ·'SW/\.· TREZ model, groundwaler levels
Field $pccification 6A 6B 7A 7B (cm) Standard crror 11.2 4.8 6.4 12.7 A vemge dcviation 14.1 7.0 8.4 16.4 CONCLUSIONS
lt seems that in spite of the inaccuracy of the soi! parameterisation, the simula -tion results are quite a good approximation of the measurement data. I f this is the case, the model can be used in practical applications in land reclamation. Of
course, it is very necessary to continue the verification commenced. A single
112 D. KOWALSKI el al. o ; 9 11 13 15 1"1 19 21 23 25 27 2') Jl
i
·20r
time [dayJ•
-40l
•
l .~
,
so
i
•
, , •
• •••
-80 t---'.~·'....!·'-**-~L--I·... · ... --·
. - - - - -
-• -•
•
-100;' Groundwater level (cm] field 6A
! -120 I 1 5 9
"
"
"
C l" ., .. -....
_
..._.
-zo -i -40!
·50 .;. 80 r•
•
-100 •Groundwater level {cm] field 68 -120 :
17
"
21•
measured
··--calculated S'NATREZ
2J
" "
29"
lime [day]•
•
•
•
•
measurcd .. _- r.;alculated SWATREZ J ° i -' -T 5 7,
"
13 15 17 19 21 23 25 27 29 31 -20 + tirne [day] .<0 -6G i • ~.
·eo .r"\' '.
i
"----.:...
• '"
• •
•
.
.
,
.
.
.
.
---~--'-- --100 , -120 .•Groundwater level [cm] field 7A __ mecalcula<lsurcd ted $INATREZ
9 11 1:3 15 17 19 21 23 25 Z"; 29 31 0+ _ _ · ... ·_····_···, -20 .,
.
-60. i • •J
·80 ~----• • r:c-,.--:---- • ··100 ,•
•
•
•
•
.120
i
Groundwałer level [cmJ field 78•
, _ _ _ .c time [day]•
•
•••
•
•
measured c:alwlatel1 SWATREZAN EMPIRlC VERlFICATION OF THE "SWATREZ" MODEL 113
verification materia!. It is also necessary to obtain proper soil parameterisatiol1 data. The "SWATREZ model also simulat~s plant growth. 1n future, the authors or
this article would like to extend their verification work to Ihis parameler.
REFERENCES
I. Brandyk T.: The fundarnentals ef moisturc rcgulation in valley soi!s (in Polish). Edition
SGGW-AR. WorsZ"W" 1990.
2. Fcddcs R.A .• Kowalik p" Zaradny H.: Simu!ation 01' field w<ller liSt! and crop yield. John
Wiley and Sons, New York· Toronto, 1978.
3. Filipcl< T. cd.: The elabon\lion of <In integrated system for city waste-w,lter t["eatmen!, with thc
irrigation or industria I crops. The main instruction <lnd research rangc (in Polish). Wyd. AR,
Lublin, 1996.
4. Zan,dny H.: Mathematical models for water and pollution transport in sn!urated and
Ullsatu-ralcd soils for Ihe requirements or irrigalion (in Polish) (manuscript). IBW PAN for
CPBR.10.8.7.I.B.12.03. project. Gdańsk 1990.
EMPIRYCZNA WERyr.IKACJA MODELU ·'SWATREZ" W WARUNKACH OBIEKTU EKSPERYMENTALNEGO "HAJDÓW"
D. Kowalski, T. Wiśniewski. H. Wróbel
Politechnika LubcIsb, ul. Nadbystrzycka 40, 20-618 Lublin, Poland
S t r e s z c z e n i c. Artykuł prezentuje wst~pną weryfikację modelu SWATREl, w warunkach
obiektu eksperymentalnego Hnjdów, zloblizowancgo \V okolicach LL1blill~. Wcryfikacj<1
obej-mowała wyniki obliczen symulacyjnych glębokosci zwierciadła wody gruntowej, w okresie jednego miesiąca. Autorzy. wybZlUąc dużą zgodnosć wyników symulacji l. pomiarami polowymi. wskazują na koniecznosć szczegółowego rozpoznania własności fizyko-wodnych prolilu glebowego.
