hydraulic performance of
controlled irrigation canals
M O D I S
U s e r ' s Guide
Appendix G of
A model to study
tfie hydraulic performance
of controlled irrigation canals
W y t z e S c h u u r m a n s
C o p y r i g h t ® b y C e n t r e f o r O p e r a t i o n a l W a t e r m a n a g e m e n t , D e l f t U n i v e r s i t y o f T e c h n o l o g y , P . O . B o x 5 0 4 8 , 2 6 0 0 G A , D e l f t , T h e N e t h e r l a n d s .
Preface
The MODIS model i s a c o m p u t e r p r o g r a m p a c k a g e w h i c h c a n be u s e d t o s t u d y t h e h y d r a u l i c p e r f o r m a n c e o f c o n t r o l l e d c a n a l s . MODIS i s an a c r o n y m o f M o d e l l i n g D r a i n a g e and I r r i g a t i o n s y s t e m s , and h a s b e e n d e v e l o p e d o u t o f t h e e x i s t i n g program RUBICON d e v e l o p e d f o r r i v e r a p p l i c a t i o n s . The u s e r ' s g u i d e c o n s i s t o f t h r e e p a r t s . T h e f i r s t f o u r c h a p t e r s p r o v i d e g e n e r a l i n f o r m a t i o n a b o u t t h e p r o g r a m p a c k a g e and i t s u s e . T h e s e c o n d p a r t ( c h a p t e r 5 t o 10) d e a l s w i t h t h e i n p u t f i l e s o f t h e p r o g r a m p a c k a g e . I n a n e x a m p l e a l l i n p u t f i l e s f o r a p a r t i c u l a r c a s e a r e w o r k e d o u t . The t h i r d a n d l a s t p a r t o f t h e u s e r ' s g u i d e ( c h a p t e r 11 a n d 1 2 ) c o n t a i n s some d e t a i l e d i n f o r m a t i o n a b o u t t h e m a t h e m a t i c s u n d e r l y i n g t h e p r o g r a m and t h e a p p l i e d n u m e r i c a l methods o f s o l u t i o n . I n a d d i t i o n t o t h e u s e r ' s g u i d e , a s o f t w a r e d o c u m e n t a t i o n o f t h e p r o g r a m p a c k a g e i s a v a i l a b l e f o r t h o s e who a r e g o i n g t o make model m o d i f i c a t i o n s .
able of contents
Description of program M O D I S
1.1 I n t r o d u c t i o n 1-1 1.2 T e c h n i c a l m e r i t 1-2 1.3 M o d e l i n g c a p a b i l i t i e s 1-4 1.4 U s e r c o n s i d e r a t i o n s 1-7 1.5 Summary and c o n c l u s i o n s 1-10Getting started
2.1 s t r u c t u r e o f t h e m o d i s program p a c k a g e 2-1 2.2 I n s t a l l a t i o n o f t h e program p a c k a g e 2-2 2.3 S t a r t i n g t h e p r o g r a m 2-3 2.4 How t o u s e t h e o p e r a t i o n t e m p l a t e ? 2-4 2.4 R u n n i n g t h e model 2-5Modelling the watermanagement system
3.1 I n t r o d u c t i o n 3-1 3.2 T h e c a n a l s y s t e m 3-1 3.3 R e g u l a t o r s 3-4 3.4 C o n t r o l o f r e g u l a t o r s 3-5 3.5 O p e r a t i o n p e r f o r m a n c e c r i t e r i a 3-7 3.6 A c c u r a c y and s t a b i l i t y 3-8 3.6.1 N u m e r i c a l a c c u r a c y 3-8 3.6.2 N u m e r i c a l s t a b i l i t y 3-11 3.7 Model c a l i b r a t i o n 3-12 3.7.1 A c c u r a c y o f i n p u t d a t a 3-12 3.7.2 C a l i b r a t i o n 3-13 V
4 Input data files
4.1 s t r u c t u r e o f i n p u t d a t a f i l e s 4-1 4.2 D a t a c o n v e n t i o n s ^""2 4.3 D a t a t y p e s 4.4 S p e c i a l i n f o r m a t i o n c h a r a c t e r s 4-45 Model definition
5.1 I n t r o d u c t i o n 5-1 5.2 I d e n t i f i c a t i o n 5-3 5.2.1 Run I d e n t i f i c a t i o n 5-3 5.2.2 s w i t c h e s 5-5 5.3 Net d e f i n i t i o n 5-7 5.3.1 Nodes 5-7 5.3.2 B r a n c h e s 5-11 5.4 G r i d d e f i n i t i o n 5-13 5.4.1 G e n e r a l c r o s s - s e c t i o n s 5-14 5.4.2 T r a p e z o i d a l c r o s s - s e c t i o n s 5-17 5.4.3 G r i d - d e f i n i t i o n 5-19 5.5 s t r u c t u r e s 5-21 5.5.1 I n t r o d u c t i o n 5-21 5.5.2 L a t e r a l d i s c h a r g e s 5-23 5.5.3 O v e r f l o w s t r u c t u r e s 5-25 5.5.4 O r i f i c e s t r u c t u r e s 5-29 5.5.5 P i p e s t r u c t u r e s 5-33 5.5.6 Pump s t r u c t u r e s 5-38 5.5.7 L o c a l l o s s s t r u c t u r e s 5-40 5.5.8 N e y r t e c d i s t r i b u t o r s 5-42 5.5.9 F o r t r a n d e f i n e d f u n c t i o n 5-45 5.6 A u t o m a t i c c o n t r o l s y s t e m s 5-48 5.6.1 I n t r o d u c t i o n 5-48 5.6.2 A u t o m a t i c l o c a l c o n t r o l 5-49 5.6.3 A u t o m a t i c r e g i o n a l c o n t r o l 5-54 5.6.4 A u t o m a t i c g l o b a l c o n t r o l 5-57 5.7 F u n c t i o n s 5-60 5.7.1 T a b u l a t e d f u n c t i o n s o f t i m e 5-60 5.7.2 G e n e r a l t a b u l a t e d f u n c t i o n s 5-625.8 I n i t i a l s t a t e 5-65
6 Model computation
6.1 I n t r o d u c t i o n 6-1 6.2 Run c o n t r o l p a r a m e t e r s 6-2 6.2.1 Run i d e n t i f i c a t i o n 6-2 6.2.2 S w i t c h e s 6-4 6.3 C o m p u t a t i o n a l p a r a m e t e r s 6-6 6.4 T i m e c o n t r o l p a r a m e t e r s 6-8 6.5 O u t p u t t o t h e s y s t e m s t a t e f i l e 6-10 6.6 O u t p u t a s a f u n c t i o n o f t i m e 6-12 6.7 O u t p u t a s a f u n c t i o n o f p l a c e 6-16 6.7.1 D e f i n i t i o n o f r o u t e s 6-16 6.7.2 B a s e f u n c t i o n 6-17 6.7.3 R e s u l t P l a c e f u n c t i o n 6-187 Result data base
7.1 I n t r o d u c t i o n 7-1 7.2 I d e n t i f i c a t i o n o f f i l e s 7-3
7.3 T r a n s f o r m a t i o n o f t i m e f u n c t i o n 7-5 7.4 I n v e s t i g a t i o n o f c o n t e n t 7-7
8 Model results, tables
8.1 I n t r o d u c t i o n 8-1 8.2 I d e n t i f i c a t i o n 8-4 8.3 S p e c i f i c a t i o n o f t a b u l a t e d o u t p u t 8-7
8.4 O p e r a t i o n p e r f o r m a n c e p a r a m e t e r s 8-9 8.5 Maxiraun mean and minimum v a l u e s 8-14
9 Model results, plots
9.1 I n t r o d u c t i o n 9-1 9.2 I d e n t i f i c a t i o n 9-2 9.3 S p e c i f i c a t i o n o f p l o t s i z e 9-5 9.4 S p e c i f i c a t i o n o f p l o t t e x t 9-7 9.5 D e f i n i t i o n o f a x e s 9-9 9.6 F u n c t i o n s p e c i f i c a t i o n 9-11 v i i
10 Example
10.1 D e s c r i p t i o n o f t h e s y s t e m 10-1 10.2 Model D e f i n i t i o n 10-4 10.3 Model c o m p u t a t i o n 1 0 - 1 0 10.4 R e s u l t D a t a B a s e 1 0 - 1 3 10.5 Model R e s u l t s T a b l e s 1 0 - 1 4 10.6 Model r e s u l t s , P l o t s 1 0 - 2 1 10.7 C o n c l u d i n g r e m a r k s 1 0 - 2 311 Mathematical background
11.1 C a n a l f l o w H - l 11.1.1 de S a i n t V e n a n t e q u a t i o n s 11-1 1 1 . 1 . 2 A s s u m p t i o n s u n d e r l y i n g t h e De S a i n t V e n a n t E q u a t i o n s 11-2 11.2 S t r u c t u r e s 1 1 . 2 . 1 I n t r o d u c t i o n 11-3 11.2.2 O v e r f l o w s t r u c t u r e s 11-4 11.2.3 O r i f i c e S t r u c t u r e s 11-7 11.2.4 P i p e 1 1 - 1 1 1 1 . 2 . 5 H e a d l e s s s t r u c t u r e s . 1 1 - 1 5 11.2.6 N e y r t e c d i s t r i b u t o r s 11-16 11.3 S t r u c t u r e o p e r a t i o n 1 1 - 1 8 11.3.1 I n t r o d u c t i o n 11-18 11.3.2 Open l o o p c o n t r o l 11-18 11.3.3 C l o s e d l o o p c o n t r o l 11-19 11.3.4 s t e p c o n t r o l l e r 11-19 1 1 . 3 . 5 PID c o n t r o l 1 1 - 2 0 11.3.6 L o c a l a n d r e g i o n a l c o n t r o l 1 1 - 2 5 11.4 E v a l u a t i o n o f s i m u l a t i o n r e s u l t s 11-26 11.4.1 I n t r o d u c t i o n 11-26 11.4.2 D e l i v e r y p e r f o r m a n c e r a t i o 11-28 1 1 . 4 . 3 O p e r a t i o n e f f i c i e n c y 11-28 11.4.4 O v e r a l l p e r f o r m a n c e 1 1 - 2 912 Numerical solution
12.1 I n t r o d u c t i o n 12-1 12.2 D i s c r e t i z i n g t h e c a n a l f l o w e q u a t i o n s 12-2 12.2.1 G e n e r a l 12-2 12.2.2 C o n t i n u i t y e q u a t i o n 1 2 - 3 12.2.3 Momentum e q u a t i o n 12-4 12.3 B o u n d a r y c o n d i t i o n s 12-7 1 2 . 3 . 1 Water l e v e l g i v e n 12-7 12.3.2 D i s c h a r g e g i v e n : 12-8 12.3.3 Q-h r e l a t i o n s h i p g i v e n 12-8 12.3.4 c r i t i c a l o u t f l o w 12-9 12.3.5 Nodal p o i n t w i t h s t o r a g e 1 2 - 1 0 1 2 . 3 . 6 Water l e v e l c o m p a t i b i l i t y 1 2 - 1 1 12.4 C o m p u t a t i o n o f a b r a n c h w i t h s t r u c t u r e s . . . 1 2 - 1 2 1 2 . 4 . 1 G e n e r a l 1 2 - 1 2 1 2 . 4 . 2 D e t e r m i n a t i o n o f t h e A B C D E c o e f f i c i e n t s 1 2 - 1 2 12.5 S o l u t i o n p r o c e d u r e 1 2 - 1 5 1 2 . 5 . 1 D e t e r m i n a t i o n o f t h e c o e f f i c i e n t s . . 1 2 - 1 5 12.5.2 S o l u t i o n o f unknowns 1 2 - 1 6 12.5.3 Boundary c o n d i t i o n s 12-18 12.6 O p e r a t i o n o f s t r u c t u r e s 1 2 - 2 0References
i x1 Description of program modis
r e p r i n t o f t h e paper "Description and evaluation of program MODIS" (schuurmans 1991) Abstract MODIS i s a n i m p l i c i t h y d r o d y n a m i c m o d e l i n g p a c k a g e t h a t h a s b e e n d e v e l o p e d t o i n v e s t i g a t e t h e h y d r a u l i c p e r f o r m a n c e o f d y n a m i c c o n t r o l l e d i r r i g a t i o n s y s t e m s . T h e m o d e l ' s most a p p a r e n t f e a t u r e s a r e i t s a c c u r a t e c o m p u t a t i o n o f a w i d e r a n g e o f s t a n d a r d s t r u c t u r e s and i t s many o p e r a t i o n p o s s i b i l i t i e s . F u r t h e r m o r e , t h e model i s a b l e t o compute p e r f o r m a n c e i n d i c a t o r s w h i c h a l l o w f o r a f a s t and d i a g n o s t i c i n t e r p r e t a t i o n o f t h e m o d e l r e s u l t s . T h e u s e r i n t e r f a c e i s n o t menu d r i v e n and t h e p r o g r a m i s n o t p u b l i c d o m a i n . T h e program i s most s u i t a b l e f o r e x p e r i e n c e d u s e r s and f o r l a r g e s y s t e m s .
1.1 Introduction
The name MODIS i s a n acronym o f " M o d e l i n g D r a i n a g e and I r r i g a t i o n S y s t e m s " , and h a s b e e n d e v e l o p e d a t D e l f t U n i v e r s i t y o f T e c h n o l o g y i n 1990. T h e c o m p u t a t i o n a l b a s e p r o g r a m u n d e r l y i n g MODIS i s t h e r i v e r m o d e l i n g p a c k a g e named R u b i c o n . T h e m a i n r e a s o n f o r i t s d e v e l o p m e n t was t h e f a c t t h a t no m o d e l s t a i l o r e d f o r c o n t r o l l e d i r r i g a t i o n c a n a l s w e r e t o be f o u n d . T h e m a i n l i m i t a t i o n s o f e x i s t i n g p r o g r a m s a r e t h e l a c k o f an a c c u r a t e c o m p u t a t i o n o f s t a n d a r d i r r i g a t i o n s t r u c t u r e s a n d t h e l i m i t e d o p e r a t i o n p o s s i b i l i t i e s o f t h e s e s t r u c t u r e s . T h e " T a s k G r o u p on R e a l Time C o n t r o l o f U r b a n D r a i n a g e S y s t e m s " a l s o comes up w i t h t h e c o n c l u s i o n s t h a t "Models for the state of the system ... have been developed in a great number for static, non-controllable systems. However, hardly any model has been described allowing to simulate automatic regulators and external control input during the simulated process". ( S c h i l l i n g 1 9 8 7 ) .
I W s guide MODIS_ _ _ _ ^ ^ _ _ _ _ _
The same c o n c l u s i o n h a s b e e n drawn two y e a r s l a t e r : ".. a key to efficient research on canal automation is the existence of an easy-to-use, accurate, and flexible unsteady flow canal hydraulic simulation program. This research project did not find such a program". ( B u r t , 1 9 8 9 )
I n t h i s p a p e r a d e s c r i p t i o n o f t h e p r o g r a m i s p r e s e n t e d f o l l o w i n g t h e " C a n a l model e v a l u a t i o n and c o m p a r i s o n c r i t e r i a " ( R o g e r s e t a l 1 9 9 1 ) . M o r e o v e r , a n a p p l i c a t i o n i s p r e s e n t e d t o i l l u s t r a t e i t s u s e . T h e a p p l i c a t i o n d e a l s w i t h t h e m o d e r n i z a t i o n o f a 110 km l o n g i r r i g a t i o n c a n a l i n J o r d a n .
1
.2
Technical Merit
Computational accuracy The model s o l v e s t h e c o m p l e t e De S a i n t V e n a n t e q u a t i o n s . T h e a p p l i e d n u m e r i c a l s o l u t i o n t e c h n i q u e i s b a s e d on f i n i t e d i f f e r e n c e s by u s i n g t h e P r e i s s r a a n n i m p l i c i t scheme. T h i s i m p l i e s t h a t t h e n u m e r i c a l method i s o f s e c o n d o r d e r a c c u r a c y i n p l a c e and, u s u a l l y , o f f i r s t o r d e r i n t i m e ( d e p e n d i n g on t h e v a l u e o f t h e t i m e i n t e r p o l a t i o n c o e f f i c i e n t ) . T h e v a l u e s o f t h e n o n - l i n e a r t e r m s a r e d e t e r m i n e d by i n t e r p o l a t i n g b e t w e e n t h e v a l u e s a t t h e o l d a n d new t i m e l e v e l , s t a r t i n g w i t h t h e v a l u e s a t t h e o l d t i m e l e v e l . The number o f i t e r a t i o n s c a n be s p e c i f i e d by t h e u s e r , b u t a v a l u e o f two i s recommended.Numerical solution criteria
The n u m e r i c a l method i s mass and momentum c o n s e r v a t i v e i f a t l e a s t two i t e r a t i o n s a r e u s e d . By u s i n g an i m p l i c i t scheme ( t h e f o u r p o i n t i m p l i c i t P r e i s s m a n n s c h e m e ) , s t a b i l i t y i s g u a r a n t e e d f o r any C o u r a n t number. T h e n u m e r i c a l s o l u t i o n c o n v e r g e s t o t h e r e a l s o l u t i o n i f t h e s o l u t i o n i s s t a b l e , b e c a u s e t h e d i f f e r e n c e e q u a t i o n s h a v e p r o v e n t o be c o n s i s t e n t w i t h t h e d i f f e r e n t i a l e q u a t i o n s (Cunge e t . a l 1 9 8 0 ) .
Description of program MODIS
R o b u s t n e s s h a s b e e n g i v e n p r i o r i t y t o a c c u r a c y . I f a c c u r a c y c o n s i d e r a t i o n s a r e v i o l a t e d a w a r n i n g m e s s a g e a p p e a r s . F o r e x a m p l e , i f i n p u t e r r o r s a r e e n c o u n t e r e d t h e model w i l l c o n t i n u e r e a d i n g t h e i n p u t d a t a , and a f t e r w a r d s p r i n t t h e e n c o u n t e r e d e r r o r s i n an e c h o f i l e o f t h e i n p u t f i l e . I n t h i s way i n p u t e r r o r s a r e w e l l t r a c e d and c a n be q u i c k l y c o r r e c t e d . To a v o i d p r o g r a m t e r m i n a t i o n i n c a s e o f d r y bed f l o w , a P r e i s s r a a n n s l o t i s a u t o m a t i c a l l y added t o t r a p e z o i d a l c r o s s - s e c t i o n s . A s p e c i a l r o u t i n e p r e v e n t s t h e s l o t f r o m f a l l i n g d r y by c o n t i n u o u s l y c h e c k i n g i f t h e w a t e r l e v e l s a r e l o w e r t h a n t h e bed l e v e l s . I f s o , t h e w a t e r d e p t h s a t t h o s e l o c a t i o n s a r e a r t i f i c i a l l y i n c r e a s e d t o 0.01 m a b o v e t h e b o t t o m l e v e l and a b a s e f l o w o f 0.001 m'/s i s g e n e r a t e d . (A w a r n i n g m e s s a g e i a p r i n t e d w h e n e v e r t h i s r o u t i n e i s a c t i v a t e d ) . Initial conditions To s o l v e t h e De S a i n t V e n a n t e q u a t i o n s i n i t i a l and b o u n d a r y c o n d i t i o n s a r e n e e d e d . The i n i t i a l c o n d i t i o n r e q u i r e s w a t e r l e v e l s and d i s c h a r g e s a t e v e r y c o m p u t a t i o n a l p o i n t a t t h e b e g i n n i n g o f t h e c o m p u t a t i o n . The u s e r h a s o n l y t o s p e c i f y i n i t i a l c o n d i t i o n s a t t h e b r a n c h e n d s , a s t h e p r o g r a m i n t e r p o l a t e s t h e v a l u e s f o r i n t e r m e d i a t e g r i d p o i n t s l o c a t e d i n t h a t b r a n c h . I t i s a l s o p o s s i b l e t o u s e t h e outcome o f a p r e v i o u s c o m p u t a t i o n a s an i n i t i a l s t a t e f o r f u r t h e r c o m p u t a t i o n s . T h i s f e a t u r e c a n be u s e d , f o r e x a m p l e , t o u s e a p r e - c a l c u l a t e d s t e a d y s t a t e a s an i n i t i a l s t a t e .Internal and extemal boundary condition analysis
The c a n a l l a y o u t i s m o d e l e d by u s i n g b r a n c h e s and n o d e s . B r a n c h e s r e p r e s e n t c o n v e y a n c e e l e m e n t s s u c h a s p o o l s o r r e a c h e s . Nodes a r e o n l y u s e d t o l i n k b r a n c h e s t o g e t h e r and t o i n d i c a t e a b r a n c h end. I n a d d i t i o n n o d e s c a n be u s e d t o model r e s e r v o i r s w h e r e b y t h e s t o r a g e a r e a c a n be s p e c i f i e d a s a f u n c t i o n o f t h e w a t e r l e v e l . E x t e r n a l b o u n d a r y c o n d i t i o n s a r e i m p o s e d on n o d e s i n d i c a t i n g b r a n c h e n d s . The u s e r c a n c h o o s e b e t w e e n a w a t e r l e v e l , d i s c h a r g e , o r s t a g e -d i s c h a r g e r e l a t i o n s h i p a s b o u n -d a r y c o n -d i t i o n . The w a t e r l e v e l an-d d i s c h a r g e c a n be s p e c i f i e d e i t h e r a s c o n s t a n t s o r a s f u n c t i o n s o f t i m e ( s t a g e h y d r o g r a p h s and d i s c h a r g e h y d r o g r a p h s ) . I n t e r n a l b o u n d a r y c o n d i t i o n s a r e n e e d e d t o l i n k b r a n c h e s , and t h e r e 1-3
User's guide MODIS _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
w a t e r l e v e l c o m p a t i b i l i t y i s a s s u m e d . S t r u c t u r e s c a n be s p e c i f i e d a n y w h e r e a l o n g a b r a n c h w i t h o u t h a v i n g t o s p e c i f y b o u n d a r y c o n d i t i o n s . The b o u n d a r y c o n d i t i o n s a r e r e w r i t t e n i n t e r n a l l y i n t h e same l i n e a r i z e d f o r m a t a s t h e m a s s and momentum e q u a t i o n s , a n d t h u s f u l l y i n c o r p o r a t e d i n t h e i m p l i c i t s o l u t i o n p r o c e d u r e . T h e b o u n d a r y c o n d i t i o n s c a n be s p e c i f i e d a s f i x e d v a l u e s , a s t i m e s e r i e s , o r a s a f u n c t i o n o f a u s e r w r i t t e n f o r t r a n r o u t i n e .Special hydraulic conditions
The model h a s a s p e c i a l r o u t i n e t o a v o i d d r y b e d f l o w i n o r d e r t o k e e p t h e model r u n n i n g . However, no s p e c i a l e q u a t i o n s a r e i n c o r p o r a t e d t o c a l c u l a t e a d v a n c e s on a d r y b e d . R a p i d f l o w c h a n g e s and b o r e w a v e s t o o a r e i n p r i n c i p a l n o t c o v e r e d by t h e De S a i n t V e n a n t e q u a t i o n s , w h i c h a r e v a l i d f o r g r a d u a l l y v a r i e d u n s t e a d y f l o w o n l y . However, t h e e r r o r made i s s m a l l a n d t h e model c a n h a n d l e r a p i d c h a n g e s q u i t e w e l l a s l o n g a s t h e C o u r a n t number i s c h o s e n s u f f i c i e n t l y c l o s e t o one and t h e t i m e i n t e r p o l a t i o n c o e f f i c i e n t i s somewhat g r e a t e r t h a n h ( C o n t r a c t o r & S c h u u r m a n s 1 9 9 1 ) . S u p e r c r i t i c a l f l o w c a n n o t be h a n d l e d . T h i s i s n o t b e c a u s e t h e De S a i n t V e n a n t e q u a t i o n s a r e n o t v a l i d f o r s u p e r c r i t i c a l f l o w , b u t i t i s due t o t h e ( d o u b l e s w e e p ) m a t r i x s o l u t i o n a l g o r i t h m . H y d r a u l i c jumps c a n o n l y be h a n d l e d i n t h e v i c i n i t y o f s t r u c t u r e s , w h e r e t h e De S a i n t V e n a n t e q u a t i o n s h a v e b e e n r e p l a c e d b y s t r u c t u r e e q u a t i o n s . R e v e r s a l o f f l o w d i r e c t i o n s w i l l c a u s e no p r o b l e m s . I t i s e v e n p o s s i b l e t o u s e d i f f e r e n t s t r u c t u r e p a r a m e t e r s f o r f l o w i n a p o s i t i v e a n d i n n e g a t i v e d i r e c t i o n .
1.3 Modeling capabilities
S y s t e m configuration The s y s t e m c o n f i g u r a t i o n i s m o d e l e d by u s i n g b r a n c h e s and n o d e s . No r e s t r i c t i o n s a r e i m p o s e d o n t h e b r a n c h l e n g t h s , and b o t h b r a n c h e d a n d l o o p e d c a n a l n e t w o r k s c a n be h a n d l e d . T h e model g e n e r a t e s a c o m p u t a t i o n a lDescription of program MODIS
T h e s e u s e r d e f i n e d g r i d p o i n t s a r e n e e d e d t o s p e c i f y t h e b r a n c h c h a r a c t e r i s t i c s s u c h a s i t s p r o f i l e and e l e v a t i o n . E v e r y g r i d p o i n t h a s an e l e v a t i o n a n d a c r o s s - s e c t i o n . The c r o s s - s e c t i o n c o n s i s t s o f a p r o f i l e s h a p e , B o u s s i n e s q c o e f f i c i e n t ( s ) and r e s i s t a n c e c o e f f i c i e n t ( s ) . A l l c o n s t r u c t i o n e l e m e n t s s u c h a s b r a n c h e s , n o d e s , g r i d p o i n t s a n d c r o s s -s e c t i o n -s h a v e u -s e r d e f i n e d name-s i n -s t e a d o f n u m b e r -s . S t r u c t u r e s h a v e t o be l o c a t e d w i t h i n a b r a n c h . A s more t h a n one s t r u c t u r e c a n be p l a c e d w i t h i n a b r a n c h , a b r a n c h c a n c o n s i s t o f v a r i o u s p o o l s s e p a r a t e d b y s t r u c t u r e s . M o r e o v e r , i t i s p o s s i b l e t o model c o m p o s i t e s t r u c t u r e s b y l o c a t i n g s e v e r a l s t r u c t u r e s a t t h e same l o c a t i o n . Frictional resistance The f r i c t i o n t e r m o f t h e De S a i n t V e n a n t E q u a t i o n s i s r e p r e s e n t e d b y S t r i c k l e r / M a n n i n g r e s i s t a n c e f o r m u l a . T h e r e s i s t a n c e v a l u e c a n be v a r i e d i n h e i g h t a n d w i t h t h e l o n g i t u d i n a l d i s t a n c e .Boundary Condition types
S t r u c t u r e s a r e n o t t r e a t e d a s b o u n d a r y c o n d i t i o n s i n t h e MODIS m o d e l , a s t h e y a r e p l a c e d w i t h i n a b r a n c h . When a s t r u c t u r e i s e n c o u n t e r e d , t h e momentum e q u a t i o n o f t h e De S a i n t V e n a n t E q u a t i o n s i s r e p l a c e d by t h e s t r u c t u r e e q u a t i o n w h i c h i s r e w r i t t e n i n t h e same f o r m a t a s t h e momentum e q u a t i o n a n d t h u s f u l l y i n c o r p o r a t e d i n t h e i m p l i c i t s o l u t i o n p r o c e d u r e . The s t a n d a r d s t r u c t u r e l i b r a r y i n c o r p o r a t e d i n t h e MODIS m o d e l c o m p r i s e s : pumps, w e i r s , o r i f i c e s , p i p e s , h e a d l o s s s t r u c t u r e s , a n d N e y r t e c b a f f l e d i s t r i b u t o r s . F u r t h e r m o r e , t h e u s e r c a n a d d h i s own w r i t t e n F o r t r a n d e f i n e d s t r u c t u r e s , b u t t h i s r e q u i r e s some k n o w l e d g e o f F o r t r a n a n d t h e p r o g r a m . S t r u c t u r e s c a n be p l a c e d i n s e r i e s and i n p a r a l l e l . T h e l a t t e r f a c i l i t y i s u s e d t o d e f i n e compound s t r u c t u r e s . S p e c i a l a t t e n t i o n h a s b e e n p a i d t o a n a c c u r a t e c o m p u t a t i o n o f s t r u c t u r e f l o w . As t h e u p s t r e a m and d o w n s t r e a m w a t e r l e v e l c a n f l u c t u a t e d u r i n g a c o m p u t a t i o n a l r u n , t h e f l o w c o n d i t i o n c a n a l s o f l u c t u a t e , e . g . from f r e e t o submerged f l o w , o r from o r i f i c e f l o w t o w e i r f l o w . T h e model c o n t i n u o u s l y c h e c k s w h i c h f l o w c o n d i t i o n i s t o be a p p l i e d , t a k i n g t h e a c t u a l s t a t e o f t h e s y s t e m i n t o a c c o u n t . Some d e f a u l t v a l u e s f o r s h i f t i n g from one f l o w c o n d i t i o n t o a n o t h e r a r e i n c o r p o r a t e d , b u t t h e u s e r c a n a l s o d e f i n e t h e s e b o u n d a r i e s h i m s e l f . M o r e o v e r , t h e v a l u e o f v a r i o u s
I W s guide MODIS_
s t r u c t u r e c o e f f i c i e n t s ( e . g . t h e c o n t r a c t i o n c o e f f i c i e n t o r e f f e c t i v e d i s c h a r g e c o e f f i c i e n t ) d e p e n d s on t h e h y d r a u l i c c o n d i t i o n s . T h e v a l u e s o f t h e s e c o e f f i c i e n t s c a n be s p e c i f i e d by t h e u s e r e i t h e r a s c o n s t a n t s o r a s a f u n c t i o n o f h y d r a u l i c p a r a m e t e r s . T u r n o u t s T u r n o u t s a r e t r e a t e d i n t h e same way a s t h e s t r u c t u r e s d e s c r i b e d i n t h e p r e v i o u s s e c t i o n . T h e u s e r h a s t o d e f i n e a b r a n c h f i r s t , a n d t h e n t o l o c a t e a s t r u c t u r e i n s i d e t h a t b r a n c h . A t t h e b r a n c h e n d a f i x e d w a t e r l e v e l c o u l d be s p e c i f i e d a s a b o u n d a r y c o n d i t i o n . O n l y i f t h e o u t f l o w r a t e i s p r e d e f i n e d , l a t e r a l i n f l o w / o u t f l o w f a c i l i t i e s c a n be u s e d w h i c h do n o t r e q u i r e a n a d d i t i o n a l b r a n c h . Operations duplicationThe MODIS model i s a b l e t o s i m u l a t e a l l t y p e s o f s t r u c t u r e o p e r a t i o n . V a r i o u s s t r u c t u r e p a r a m e t e r s s u c h a s w i d t h , s i l l l e v e l , and g a t e o p e n i n g h e i g h t c a n b e g i v e n a c o n s t a n t v a l u e o r c a n be s p e c i f i e d a s f u n c t i o n s . T h e r e c a n be t i m e f u n c t i o n s , b u t a l s o f u n c t i o n s o f e.g. an u p s t r e a m w a t e r l e v e l . Pumps a r e s w i t c h e d on i f t h e a c t u a l w a t e r l e v e l e x c e e d s a u s e r d e f i n e d l e v e l , and s w i t c h e d o f f i f t h e a c t u a l w a t e r l e v e l d r o p s b e l o w a n o t h e r l o w e r u s e r d e f i n e d l e v e l . ( T h e s e l e v e l s i n t u r n c a n be s p e c i f i e d a s a f u n c t i o n o f t i m e ) . M o r e o v e r , t h e c a p a c i t y o f t h e pump c a n b e s p e c i f i e d a s a f u n c t i o n o f t h e h e a d . Automatic control I t i s o b v i o u s t h a t i t i s i r r e l e v a n t f o r t h e b e h a v i o u r o f t h e s y s t e m w h e t h e r o p e r a t i o n i s c a r r i e d o u t m a n u a l l y o r a u t o m a t i c a l l y . A u t o m a t i c c o n t r o l a s a f u n c t i o n o f t i m e and o n / o f f c o n t r o l c a n t h e r e f o r e b e m o d e l l e d i n t h e same way a s d e s c r i b e d i n 3.5. I n MODIS i t i s a l s o p o s s i b l e t o s i m u l a t e r e a l t i m e c o n t r o l ( c l o s e d l o o p c o n t r o l ) w h e r e b y c o n t r o l i s b a s e d on t h e a c t u a l s t a t e o f t h e s y s t e m f o l l o w i n g a c o n t r o l a l g o r i t h m .
S e v e r a l t y p e s o f c o n t r o l a l g o r i t h m s h a v e b e e n i m p l e m e n t e d i n t h e MODIS m o d e l : a m u l t i p l e s p e e d c o n t r o l l e r , a P r o p o r t i o n a l I n t e g r a l
DföcripdtHi of program MODIS_
L i n e a r i z e d Q u a d r a t i c G a u s s i a n C o n t r o l . F o r e a c h c o n t r o l l e r c o n t r o l p a r a m e t e r s h a v e t o be s p e c i f i e d . T h e s e c o n t r o l p a r a m e t e r s , s u c h a s g a i n f a c t o r s , c a n be s p e c i f i e d a s c o n s t a n t s , b u t a l s o a s a f u n c t i o n of t i m e o r a h y d r a u l i c v a r i a b l e . T h u s , t h e t a r g e t l e v e l s of t h e c o n t r o l l e r s c a n be a d j u s t e d i n t i m e and t h e s p e e d of g a t e movement c a n be s p e c i f i e d a s a f u n c t i o n o f t h e d e v i a t i o n from t h e s e t - p o i n t . F i n a l l y , d i f f e r e n t l e v e l s o f c o n t r o l c a n be d e f i n e d s u c h a s l o c a l and r e g i o n a l c o n t r o l . As a r e s u l t , a l l t y p e s o f e x i s t i n g c a n a l c o n t r o l s y s t e m s , s u c h a s u p s t r e a m c o n t r o l , d o w n s t r e a m c o n t r o l , m i x e d c o n t r o l , B I V A L c o n t r o l , E L F L O W - c o n t r o l and C A R D D - c o n t r o l c a n be m o d e l l e d i n t h e MODIS model. U s e r d e f i n e d c o n t r o l a l g o r i t h m s c a n be added t o t h e model by u s i n g t h e F o r t r a n f u n c t i o n f a c i l i t y .Miscellaneous limitations
Model l i m i t a t i o n s a r e m a i n l y r e l a t e d t o memory l i m i t a t i o n s . The u s e r c a n t a i l o r i t s model f o r a s p e c i f i c p r o j e c t by c h a n g i n g t h e maximum number o f b r a n c h e s , n o d e s , s t r u c t u r e s , f u n c t i o n s , c o n t r o l l e r s , e t c e t e r a . I n o r d e r t o do so, t h e u s e r h a s t o r e d e f i n e some maximum p a r a m e t e r s and t o r e - c o m p i l e t h e c o m p l e t e model p a c k a g e . T h e r e a r e no l i m i t a t i o n s t o p h y s i c a l d i m e n s i o n s . B o t h t r a p e z o i d a l and i r r e g u l a r c r o s s - s e c t i o n s c a n be m o d e l l e d . The minimum c o m p u t a t i o n a l t i m e s t e p i s 1 s e c o n d . The u s e r c a n d e f i n e t h e r e q u i r e d f o r m a t o f t h e o u t p u t d a t a and t h u s p r e s e n t s t h e w a t e r l e v e l s a s p r e c i s e a s he w a n t s .
1.4 User considerations
U s e r interface
The MODIS model i s c o n t r o l l e d from an o p e r a t i o n t e m p l a t e w h i c h i s shown on t h e s c r e e n . By m o v i n g a h i g h l i g h t e d b a r t h r o u g h t h e t e m p l a t e t o a s p e c i f i c i t e m and by p r e s s i n g a h e l p key, i n f o r m a t i o n a b o u t t h e s e l e c t e d i t e m i s p r o v i d e d . The p r o g r a m c o n s i s t s o f s e v e r a l sub p r o g r a m s w h i c h have t o be r u n i n s e q u e n c e . E v e r y s u b p r o g r a m h a s i t s own i n p u t f i l e and p r o d u c e s b o t h an e c h o f i l e w i t h e r r o r m e s s a g e s , and an o u t p u t f i l e . E a c h i n p u t d a t a f i l e i s f i r s t c h e c k e d on p o s s i b l e e r r o r s b e f o r e e x e c u t i o n o f
LWs guide MODIS_
t h e program. The e r r o r messages, d i v i d e d i n t o w a r n i n g s , e r r o r s , and f a t a l
e r r o r s , a r e p r i n t e d i n an echo f i l e o f t h e i n p u t f i l e .
The i n p u t d a t a ( i n m e t r i c u n i t s o n l y ) can be found i n i n p u t f i l e s .
I n t e r a c t i v e d a t a i n p u t i s n o t p o s s i b l e . An i n p u t f i l e comprises i n p u t
t a b l e s s u p p o r t e d by e x p l a n a t o r y comment l i n e s . The i n p u t d a t a has t o be
s p e c i f i e d i n t h e i n p u t t a b l e s f o l l o w i n g a p r e - d e s c r i b e d sequence, b u t no
f i x e d column p o s i t i o n i s needed. Both names and numbers can be used t o
denote s t r u c t u r e s , branches, nodes, f u n c t i o n s , c o n t r o l l e r s e t c e t e r a .
To f a c i l i t a t e easy d a t a i n p u t , s p e c i a l i n f o r m a t i o n c h a r a c t e r s can be
used t o reduce t h e amount o f i n p u t d a t a . For example, t h e symbol
means t h a t t h e v a l u e i s e q u a l t o t h e v a l u e o f t h e same column s p e c i f i e d
above. The symbol s t a n d s f o r i n t e r p o l a t i o n o f data s p e c i f i e d i n t h e
same column above and below. F u r t h e r m o r e , a l l e d i t o r f e a t u r e s such as
" f i n d and r e p l a c e " , "copy", and "move" a r e a v a i l a b l e . P r a c t i c e has shown
t h a t t h e use o f i n p u t f i l e s i n s t e a d o f a menu d r i v e n i n p u t might be
overwhelming f o r t h e f i r s t t i m e u s e r , whereas t h e more e x p e r i e n c e d u s e r
f i n d s i t s way e a s i l y and q u i c k l y .
The f i n a l c o m p u t a t i o n a l r e s u l t s , as f u n c t i o n s o f t i m e o r p l a c e , can
be p r e s e n t e d b o t h g r a p h i c a l l y and i n t a b l e s . P o s s i b l e o u t p u t parameters
a r e : water l e v e l s , water d e p t h s , d i s c h a r g e s , w e t t e d c r o s s - s e c t i o n a l a r e a ,
f l o w w i d t h , s t o r a g e w i d t h , Boussinesq c o e f f i c i e n t , h y d r a u l i c r a d i u s ,
r e s i s t a n c e , Froude number. The c o l o u r e d graphs can be p r i n t e d on v a r i o u s
t y p e s o f screens and on a wide v a r i e t y o f p r i n t e r s and p l o t t e r s .
To f a c i l i t a t e an easy i n t e r p r e t a t i o n , i t i s p o s s i b l e t o p r i n t o n l y
maximum, mean, and minimum v a l u e s a t c e r t a i n l o c a t i o n s d u r i n g a s p e c i f i c
p e r i o d s o f t i m e . F u r t h e r m o r e , t h e p e r c e n t a g e o f t i m e i n w h i c h u s e r
d e f i n e d minimum and maximum v a l u e s have been exceeded can be p r i n t e d .
To e v a l u a t e t h e w a t e r d i s t r i b u t i o n i n i r r i g a t i o n systems s i m u l a t e d
by t h e MODIS model, o p e r a t i o n p e r f o r m a n c e i n d i c a t o r s which a r e computed
by t h e model can be used. They c o n s i s t o f a d e l i v e r y performance r a t i o
(DPR), w h i c h s p e c i f i e s t o which e x t e n t t h e user i n t e n d e d d i s t r i b u t i o n i s
s a t i s f i e d , and an o p e r a t i o n e f f i c i e n c y (e,,) , w h i c h i n d i c a t e s how much
water i s l o s t due t o i n a p p r o p r i a t e o p e r a t i o n and leakage (Schuurmans S
Maherani, 1 9 9 1 ) .
Etecripdoo of program MODIS
Documentation and support
The program package i s s u p p o r t e d by a u s e r ' s manual, i n w h i c h a l s o
examples a r e p r e s e n t e d . Furthermore, an updated s o f t w a r e d o c u m e n t a t i o n
i s a v a i l a b l e c o n t a i n i n g an a l p h a b e t i c l i s t o f a l l p a r a m e t e r s , a l l
s u b r o u t i n e s and Hipo diagrams o f each subprogram. P u r c h a s e r s o f t h e
program can g e t a s s i s t a n c e b o t h from D e l f t U n i v e r s i t y o f Technology and
from Haskoning C o n s u l t i n g Engineers who d e v e l o p e d t h e base r i v e r m o d e l i n g
package "Rubicon" o u t o f which MODIS was d e v e l o p e d .
Direct costs
The e x e c u t a b l e v e r s i o n o f t h e program package c o s t s about ƒ 25,000 and
t o o b t a i n t h e source code an a d d i t i o n a l amount i s needed, depending on
the a p p l i c a t i o n s . The program can r u n on any I B M - c o m p a t i b l e computer w i t h
6A0 KB Ram memory, equipped w i t h a m a t h e m a t i c a l c o - p r o c e s s o r and w i t h a
h a r d d i s k . The program performs most w e l l on an AT-computer w i t h a 80286
or h i g h e r p r o c e s s o r . For t h e g r a p h i c a l o u t p u t , t h e commercial "HALO"
g r a p h i c a l package i s needed.
Indirect costs
I t t a k e s one day t o g e t f a m i l i a r w i t h t h e program and t o know where t o
f i n d what i n t h e user's guide. To d e f i n e a model o f t h e i r r i g a t i o n system
u s i n g t h e MODIS package r e q u i r e s a n o t h e r few days, depending on t h e s i z e
of t h e system. A p a r t from c a l i b r a t i o n ( i f needed) most o f t h e t i m e i s
i n v o l v e d i n d e t e r m i n i n g which runs have t o be made and how t o i n t e r p r e t
t h e r e s u l t s . T h i s r e q u i r e s a s k i l l e d watermanagement e n g i n e e r f o r
o p e r a t i o n r a t h e r t h a n a computer s p e c i a l i s t . To f i n d a sound s o l u t i o n
s e v e r a l s i m u l a t i o n s a r e u s u a l l y r e q u i r e d . I n t e r p r e t a t i o n o f t h e model
r e s u l t s i s f a s t e n e d w i t h t h e h e l p o f t h e model i n t e r p r e t a t i o n parameters
which a l s o do have some d i a g n o s t i c i m p o r t a n c e . The model e x e c u t i o n t i m e
depends on t h e s i z e o f t h e model. Even f o r l a r g e i r r i g a t i o n systems w i t h
hundreds o f g r i d p o i n t s and more t h a n a hundred s t r u c t u r e s i t w i l l t a k e
l e s s t h a n a second t o proceed one c o m p u t a t i o n a l s t e p on a 386 machine.
T h i s i m p l i e s t h a t t h e t o t a l s i m u l a t i o n t i m e r e q u i r e d t o s i m u l a t e a few
days i s a m a t t e r o f minutes.
LWs guide MODIS_
1.5 Summary and conclusions
A g r e a t number o f f l o w models w h i c h c a l c u l a t e t h e unsteady f l o w phenomena
i n one d i m e n s i o n a l c a n a l systems do e x i s t . Each program has i t s own
c h a r a c t e r i s t i c s and l i m i t a t i o n s . The MODIS model was d e v e l o p e d e s p e c i a l l y
t o s t u d y t h e h y d r a u l i c performance o f c o n t r o l l e d i r r i g a t i o n c a n a l s . I n
t h a t r e s p e c t s p e c i a l a t t e n t i o n has been p a i d t o an a c c u r a t e c o m p u t a t i o n
o f s t r u c t u r e f l o w and a wide range o f o p e r a t i o n c o n c e p t s . A l t h o u g h t h e
program i s n o t menu d r i v e n , i t has proven t o be c o n v e n i e n t f o r more
e x p e r i e n c e d u s e r s and l a r g e c a n a l systems. MODIS i s a commercial program
package and n o t p u b l i c domain.
References
B u r t , C h a r l e s ( 1 9 8 9 ) , "Canal Automation P r o v i d i n g On-Demand Water
D e l i v e r i e s f o r E f f i c i e n t I r r i g a t i o n " , Department o f A g r i c u l t u r a l
E n g i n e e r i n g , C a l i f o r n i a P o l y t e c h n i c S t a t e U n i v e r s i t y ( C a l P o l y ) , San
L u i s Obispo, CA 9 3 4 0 7 , U.S.A.
Cunge, J.A., F.M. H o l l y , A. Verwey ( 1 9 8 0 ) , " P r a c t i c a l A s p e c t s o f
C o m p u t a t i o n a l R i v e r H y d r a u l i c s " , Pitman P u b l i s h i n g L i m i t e d , London.
C o n t r a c t o r D.N., W. Schuurmans ( 1 9 9 1 ) , " I n f o r m e d use and p o t e n t i a l o f
c a n a l models", ASCE N a t i o n a l Conference on I r r i g a t i o n and Drainage
E n g i n e e r i n g , H a w a i i .
Haskoning, Jouzy & P a r t n e r s ( 1 9 9 1 ) , " R e h a b i l i t a t i o n and u p g r a d i n g o f t h e
K i n g A b d u l l a h Canal, H y d r a u l i c model f o r c a l c u l a t i o n and a n a l y s i s o f
t h e w a t e r i n u n s t e a d y s t a t e c o n d i t i o n s " , Nijmegen, The N e t h e r l a n d s .
Rogers D.C, J. K e i t h and W. Schuurmans ( 1 9 9 1 ) , "Canal model e v a l u a t i o n
and c o m p a r i s o n c r i t e r i a " , ASCE N a t i o n a l Conference on I r r i g a t i o n and
D r a i n a g e E n g i n e e r i n g , H a w a i i .
S c h i l l i n g W. ( 1 9 8 7 ) , "Real Time C o n t r o l o f Urban D r a i n a g e Systems, The
B t a t e - o f - t h e a r t " , lAWPRC/IAHR J o i n t Committee,
schuurmans W., M. Maherani ( 1 9 9 1 ) , " O p e r a t i o n a l performance o f c a n a l
c o n t r o l systems", Water Resources Management, Kluwer Academic Press,
2 Getting started
2.1 Structure of the modis program package
The MODIS program package c o n s i s t s o f f i v e e x e c u t a b l e submodels which can
be p r o c e s s e d i n d i v i d u a l l y . The i n p u t d a t a o f each submodule a r e read from
an u s e r s p e c i f i e d i n p u t f i l e and p o s s i b l y f r o m i n t e r n a l o u t p u t f i l e s ,
which have been produced by a p r e v i o u s submodule.
When a submodule i s executed i t produces two o u t p u t f i l e s which can be
l o o k e d up by t h e user. The f i r s t i s a s o - c a l l e d "echo f i l e " which
c o n t a i n s a copy (echo) o f t h e i n p u t f i l e , t o which p o s s i b l e e r r o r
messages a r e added. The second o u t p u t f i l e i s a normal o u t p u t f i l e and
c o n t a i n s t h e processed d a t a . The o u t p u t f i l e s o f some submodules a r e
n o r m a l l y o f no i n t e r e s t t o t h e u s e r . The most i m p o r t a n t o u t p u t f i l e s , a r e
the ones c o n t a i n i n g t h e r e s u l t s o f t h e c o m p u t a t i o n s (Output t a b l e s and
p l o t s ) .
The main s t r u c t u r e o f MODIS, c o n t a i n i n g t h e f i v e e x e c u t a b l e submodules
i s shown i n F i g u r e 2.1.1.
INPUT DEFINITION
I
COMPUTATION
RESULT DATA BASE
OUTPUT TABLES
OUTPUT PLOTS
F i g u r e 2.1.1 Main structure of program package MODIS
User's guide MODlS_
2.2 Installation of the program package
The MODIS program package c o n s i s t s o f f i v e e x e c u t a b l e subraodules and one
menu subraodule. Each submodule s h o u l d be l o c a t e d i n a s p e c i f i c
s u b d i r e c t o r y under t h e main d i r e c t o r y "MODIS" o f w h i c h t h e names a r e
g i v e n i n F i g u r e 2.2.1.
OTHER
3HODMEN I MODDEF
I
MODCOM RDBUTL| MODRES
1
HODPLT
c : \
I
1MODIS moddef raodcom r d b u t l modres modplt
* . t x t
IRRI
M DEMO
M PROJECT
d e f i n . d a t
defech.dat
d e f o u t . d a t
e t c e t e r a
Figure 2.2.1 Location of submodules in subdirectories
For more d e t a i l e d i n f o r m a t i o n about t h e s t r u c t u r e and l o c a t i o n o f t h e
system f i l e s , r e f e r e n c e i s made t o c h a p t e r 13. W i t h t h e h e l p o f t h e
i n s t a l l a t i o n program l o c a t e d on d i s k e t t e no. 1, t h e r e q u i r e d d i r e c t o r i e s
are made a u t o m a t i c a l l y and t h e submodules a r e a u t o m a t i c a l l y c o p i e d t o t h e
r i g h t d i r e c t o r i e s . I n o r d e r t o r u n t h e i n s t a l l a t i o n program, p u t d i s k e t t e
no. 1 i n d r i v e A and t y p e t h e f o l l o w i n g MS-DOS command l i n e ( f o l l o w e d by
< e n t e r > ) :
A: \ i n s t a l l
Getting started
2
. 3 Starting
tlie
program
Making a (lefault directory
The u s e r o f MODIS i s a d v i s e d t o work i n new d i r e c t o r i e s f o r e v e r y new
p r o j e c t , t h e so c a l l e d "working d i r e c t o r y " , as t o a v o i d o v e r w r i t i n g o f
e x i s t i n g d a t a . To make t h i s " w o r k i n g d i r e c t o r y " , t h e user has t o t y p e t h e
f o l l o w i n g command l i n e s , each l i n e t e r m i n a t e d by p r e s s i n g t h e < e n t e r >
key!
cd \
md IRRI
cd IRRI
Now t h e w o r k i n g d i r e c t o r y \IRRI has been c r e a t e d and i s c o n s e q i j e n t l y t h e
d e f a u l t d i r e c t o r y from which t h e program MODIS can be s t a r t e d . T h i s
i m p l i e s t h a t a l l i n p u t data f i l e s and a l l r e s u l t f i l e s a r e w r i t t e n and
r e a d from t h i s d i r e c t o r y .
Starting the program
The program MODIS i s now s t a r t e d by t y p i n g t h e f o l l o w i n g MS-DOS command
l i n e ( t e r m i n a t e d by < e n t e r > ) :
C:\MODIS\MODMEN\MODIS.EXE
Tip 1 When a new w o r k i n g d i r e c t o r y i s made i t i s a d v i s e d t o copy
a l r e a d y e x i s t i n g i n p u t f i l e s from an o l d w o r k i n g d i r e c t o r y t o t h i s new
w o r k i n g d i r e c t o r y . I n t h i s way a l l s t a n d a r d i n p u t d a t a o f t h e i n p u t f i l e s
do n o t have t o be r e t y p e d and o n l y d a t a d e s c r i b i n g t h e w a t e r management
system s h o u l d be a l t e r e d . I n o r d e r t o copy t h e d e m o n s t r a t i o n i n p u t d a t a
f i l e s t o t h e working d i r e c t o r y , t h e f o l l o w i n g MS-DOS command l i n e s h o u l d
be g i v e n b e f o r e s t a r t i n g t h e program: COPY \IRRI\M_DEMO\*.DAT
Tip 2 To f a c i l i t a t e t h e s t a r t o f MODIS from e v e r y d i r e c t o r y w i t h o u t
h a v i n g t o type t h e whole p a t h , t h e f o l l o w i n g s t a t e m e n t s h o u l d be i n c l u d e d
i n t h e autoexec.bat f i l e : PATH \MODIS\MODMEN
User's guide M0D1S_
2.4 How to use the operation template ?
vmen t h e computer program i s s t a r t e d , an i n t r o d u c t i o n s c r e e n appears
showing t h e name MODIS and t h e v e r s i o n o f t h e program. When any key i s
h i t t h e program s k i p s t o t h e o p e r a t i o n t e m p l a t e as shown i n F i g . 2.4.1. .
Using t h e arrow key, t h e user can move t h e h i g h l i g h t e d b a r t h r o u g h t h e
t e m p l a t e . To s e l e c t a h i g h l i g h t e d i t e m , s i m p l y p r e s s t h e < e n t e r > key.
I n a d d i t i o n t o t h e s e l e c t i o n o f an i t e m , v a r i o u s o t h e r f u n c t i o n s can be
performed from t h e o p e r a t i o n t e m p l a t e . An o v e r v i e w o f t h e s p e c i a l keys
and t h e i r f u n c t i o n i s p r e s e n t e d i n Table 2.4.1.. When p r e s s i n g t h e <esc>
key f o r example, a g e n e r a l h e l p screen w i l l be shown, w h i c h e x p l a i n s t h e
f u n c t i o n o f s p e c i a l keys. To g e t h e l p i n f o r m a t i o n about a h i g h l i g h t e d
i t e m on t h e o p e r a t i o n t e m p l a t e ( f o r example about t h e i n p u t o f t h e model
d e f i n i t i o n ) s i m p l y p r e s s t h e < F l > f u n c t i o n key.
To t e r m i n a t e t h e program package MODIS, move t h e h i g h l i g h t e d b a r on "END
OF MODIS" (by u s i n g t h e arrow keys o r by p r e s s i n g t h e <end> k e y ) f o l l o w e d
by < e n t e r > . To go t e m p o r a r i l y t o t h e MS-DOS o p e r a t i n g system, p r e s s t h e
< F 2 > f u n c t i o n key. You can r e t u r n t o t h e o p e r a t i o n t e m p l a t e by t y p i n g
EXIT, f o l l o w e d by < r e t u r n > .
I I H O D I S
OPERATION TEMPLATE DATE :
0 3 - 0 B - 8 9SUBPROGRAM
INPUT RUN ECHO OUTPUT
DEFINITION
COMPUTATION
RESULT DBASE
OUTPUT TABLES
OUTPUT PLOT
I R E 0
I R E 0
I R E 0
I R E 0
I R E 0
COMPLETE MODEL RUN
Getting started
T A B L E 2.4.1 Special l<eys of the operation template
FUNCTION
< e n t e r >
<ESC>
< F l >
< F 2 > < F 3 > < F 4 ><END>
<CURS0R UP>
<CURSOR D0WN>
<CURS0R LEFT>
<CURSOR RIGHT>
S e l e c t t h e h i g h l i g h t e d i t e m .
General h e l p i n f o r m a t i o n .
Help i n f o r m a t i o n about t h e h i g h l i g h t e d i t e m .
Go t o DOS.
Back-up o f a l l i n p u t d a t a f i l e s
Copy a back-up i n p u t f i l e s t o t h e w o r k i n g
d i r e c t o r y
Moves h i g h l i g h t e d bar t o "END OF MODIS".
Moves h i g h l i g h t e d bar up.
Moves h i g h l i g h t e d b a r down.
Moves h i g h l i g h t e d bar t o t h e l e f t .
Moves h i g h l i g h t e d bar t o t h e r i g h t .
2.5 Running the model
As e x p l a i n e d i n paragraph 2.1 " S t r u c t u r e o f t h e MODIS program package",
t h e package c o n s i s t s o f f i v e e x e c u t a b l e submodules which have t o be
e x e c u t e d f o l l o w i n g a c e r t a i n sequence.
Model definition
F i r s t t h e i n p u t f i l e o f t h e model d e f i n i t i o n has t o be p r e p a r e d f o r
e x e c u t i o n . I n c h a p t e r f i v e a d e t a i l e d d e s c r i p t i o n o f t h i s i n p u t f i l e i s
g i v e n . When t h e i n p u t f i l e has been completed, t h e submodule MODEL
DEFINITION i s e x e c u t e d . T h i s i s a c h i e v e d by s t e e r i n g t h e h i g h l i g h t e d b a r
t o row DEFINITION and column RUN and p r e s s i n g < e n t e r > . A f t e r e x e c u t i o n
a message w i l l appear on t h e s c r e e n w i t h t h e number o f e r r o r s made. When
e r r o r s have been found, t h e echo f i l e o f t h e model d e f i n i t i o n i s checked
i n s e a r c h o f t h e d e t e c t e d e r r o r s . Of course t h e marked e r r o r s a r e n o t t o
be c o r r e c t e d i n t h e echo f i l e , b u t i n t h e i n p u t f i l e . When t h e d e t e c t e d
User's guide MODIS
e r r o r s have been c o r r e c t e d , t h e model d e f i n i t i o n i s processed once more.
T h i s p r o c e d u r e must be r e p e a t e d u n t i l t h e r e a r e no more e r r o r s t o be
found. When d e s i r e d , t h e o u t p u t f i l e o f t h e model d e f i n i t i o n can be
l o o k e d up o r p r i n t e d t o g e n e r a t e a good p r e s e n t a t i o n o f t h e i n p u t d a t a .
Other submodules
T h i s p r o c e d u r e o f p r e p a r i n g t h e i n p u t f i l e , r u n n i n g a submodule and
c o r r e c t i n g p o s s i b l e e r r o r s u n t i l no more e r r o r s a r e b e i n g f o u n d , s h o u l d
be f o l l o w e d f o r a l l t h e o t h e r subraodules as w e l l . The sequence i n which
the submodules s h o u l d be executed has been l i s t e d beneath :
- Model D e f i n i t i o n
- Model Computation
- R e s u l t Dbase
3 Modelling the watermanagement system
3.1 Introduction
I n t h i s c h a p t e r t h e p r i n c i p l e s o f how t o model a watermanagement system
i n t h e MODIS computer package and o f how t o make s i m u l a t i o n s and
e v a l u a t i o n s , are e x p l a i n e d . The MODIS model has a wide range o f elements
w i t h which t h e user can e a s i l y model n e a r l y any watermanagement system.
The c o n s t r u c t i o n elements c o m p r i s e : branches, nodes, g r i d p o i n t s , c r o s s
-s e c t i o n -s , r e g u l a t o r -s e t c e t e r a . The l a y - o u t o f t h e c a n a l -sy-stem i -s d e f i n e d
by u s i n g branches connected by nodes. I t i s p o s s i b l e t o model b o t h
branched and looped n e t w o r k s . ( I t i s n o t necessary t o l i m i t t h e branch
l e n g t h from a c o m p u t a t i o n a l p o i n t o f v i e w , as t h e model w i l l g e n e r a t e a
c o m p u t a t i o n a l g r i d over t h e branches a f t e r w a r d s ) . The c a n a l c r o s s
-s e c t i o n -s a r e a t t a c h e d t o t h e branche-s by u -s i n g ( c o m p u t a t i o n a l ) g r i d
p o i n t s which are p l a c e d on t h e branches. Concerning t h e r e g u l a t o r s , t h e
user can d e s c r i b e n e a r l y any s t r u c t u r e as a wide range o f s t a n d a r d
s t r u c t u r e s i s a v a i l a b l e i n MODIS.
The o p e r a t i o n elements comprise t h e v a r i o u s a l t e r n a t i v e s f o r o p e r a t i o n
of t h e r e g u l a t o r s , v a r y i n g from manual o p e r a t i o n t o a u t o m a t i c
c o m p u t e r i z e d o p e r a t i o n . F u r t h e r m o r e t h e o p e r a t i o n performance c r i t e r i a
which a l l o w f o r a f a s t , d i a g n o s t i c and c o m p a r a t i v e e v a l u a t i o n o f
o p e r a t i o n a l t e r n a t i v e s a r e c o n s i d e r e d as " o p e r a t i o n e l e m e n t s " .
3.2 The canal system
Configuration
The c a n a l c o n f i g u r a t i o n i s schematized u s i n g branches and nodes. A branch
i s a conveyance element and has a c e r t a i n l e n g t h . A node i s an element
User's guide MODIS
used t o connect branches o r t o i n d i c a t e a branch end. Both branched and l o o p e d c a n a l n e t w o r k s can be h a n d l e d by MODIS. The l e n g t h o f a b r a n c h i s n o t l i m i t e d and i t i s n o t r e q u i r e d t o use branches o f t h e same l e n g t h .
Boundary conditions
A t e v e r y node an e x t e r n a l o r i n t e r n a l boundary c o n d i t i o n has t o be s p e c i f i e d . For a node t h a t c o n n e c t s branches, t h e i n t e r n a l boundary c o n d i t i o n i s u s u a l l y t h e c o m p a t i b i l i t y o f t h e w a t e r l e v e l s i n t h e c o n n e c t e d b r a n c h e s . For a node a t a b r a n c h end, t h e e x t e r n a l boundary c o n d i t i o n can be a s p e c i f i e d w a t e r l e v e l , d i s c h a r g e o r any r e l a t i o n s h i p between t h e w a t e r l e v e l and d i s c h a r g e ( f o r i n s t a n c e an end s p i l l w a y ) .
N o r m a l l y no w a t e r i s s t o r e d a t a node i t s e l f and a l l s t o r a g e i s l o c a t e d i n t h e branches. I n some s p e c i a l cases however, i t i s c o n v e n i e n t t o a l l o w f o r s t o r a g e a t a node, e.g. t o model a n i g h t r e s e r v o i r . I n t h a t case t h e node has a s t o r a g e area e q u a l t o Ag. The s t o r a g e area Aj i s assumed t o e q u a l z e r o by d e f a u l t .
Each b r a n c h and node must be g i v e n an u n i q u e name. F i g u r e 3.2.1 shows an example o f t h e use o f branches and nodes i n a m o d e l l e d c a n a l system.
Dimensions
The d i m e n s i o n s o f t h e c a n a l p r o f i l e and t h e bed s l o p e o f t h e c a n a l s a r e g i v e n by " g r i d p o i n t s " . A g r i d p o i n t i s a c o m p u t a t i o n a l p o i n t l o c a t e d a t a b r a n c h . Each g r i d p o i n t has a name, a r e f e r e n c e l e v e l and a c r o s s -s e c t i o n ( i n c l u d i n g Manning'-s o r S t r i c k l e r roughne-s-s c o e f f i c i e n t and t h e B o u s s i n e s q c o e f f i c i e n t ) . Every b r a n c h must be bounded by g r i d p o i n t s , one a t each end. ( I n t h e nodes no w a t e r l e v e l o r d i s c h a r g e i s computed and t h e r e f o r e c o m p u t a t i o n a l g r i d p o i n t s a r e n e c e s s a r y ) . By d e f i n i n g t h e s e g r i d p o i n t s i n a b r a n c h , t h e b r a n c h w i l l o b t a i n a bed s l o p e ( i m p l i e d by t h e r e f e r e n c e l e v e l s o f t h e g r i d p o i n t s ) , a c r o s s - s e c t i o n a l p r o f i l e and a roughness.
Modelling the watenuanagenitnt sjstein
e q u a t i o n s and t h e f l o w t h r o u g h t h e r e g u l a t o r s . G r i d p o i n t s a r e used t o
d i s c r e t i z e t h e b r a n c h . T h i s i s r e q u i r e d f o r n u m e r i c a l i n t e g r a t i o n o f t h e
p a r t i a l d i f f e r e n t i a l e q u a t i o n s d e s c r i b i n g t h e g r a d u a l l y v a r i e d unsteady
f l o w . I n MODIS a c o m p u t a t i o n a l g r i d w i t h s e v e r a l i n t e r m e d i a t e g r i d - p o i n t s
i s a u t o m a t i c a l l y g e n e r a t e d between t h e user d e f i n e d g r i d p o i n t s i n a
b r a n c h . The u s e r j u s t has t o s p e c i f y t h e maximum d i s t a n c e between t h e
a u t o m a t i c a l l y g e n e r a t e d g r i d p o i n t s . I n t h i s way t h e u s e r can e a s i l y v a r y
t h e s t e p s i z e Ax and c o n t r o l t h e n u m e r i c a l e r r o r s . The c r o s s - s e c t i o n a l
d a t a a t t a c h e d t o t h e a u t o m a t i c a l l y generated g r i d p o i n t s a r e o b t a i n e d by
i n t e r p o l a t i o n f r o m t h e a d j a c e n t user d e f i n e d g r i d p o i n t s .
OJt.2 O t t . i 011-4 o u - s OII-O U p s l f C D m c o n t r o l a l t e r n a t i v e 0 ( t . 2 0 I ( . 3 O t M o n - GT
Downslreom conlrol ettemntive L E G E N D
Main eerv^ emmmmm
T
Figure 3.2.1 Example of a modelled canal system
C r o s s - s e c t i o n s
As mentioned b e f o r e t h e c r o s s - s e c t i o n a l data o f a b r a n c h a r e s p e c i f i e d
v i a g r i d p o i n t s . Each g r i d p o i n t r e f e r s t o a c r o s s - s e c t i o n a l name. T h i s
name i s a t t a c h e d t o a c r o s s - s e c t i o n a l t a b l e . I n each c r o s s - s e c t i o n a l
t a b l e , t h e c a n a l p r o f i l e (any shape i s p o s s i b l e ) , t h e Boussinesq
c o e f f i c i e n t and t h e Manning o r S t r i c k l e r roughness c o e f f i c i e n t are b e i n g
s p e c i f i e d .
User's guide M0D1S_
3.3 Regulators
R e g u l a t o r s can be d e f i n e d a t any p l a c e a l o n g a branch. The MODIS model
package o f f e r s a wide range o f s t a n d a r d s t r u c t u r e s f o r b o t h f r e e and
submerged f l o w c o n d i t i o n s . The model a u t o m a t i c a l l y s w i t c h e s t o t h e r i g h t
f l o w c o n d i t i o n and i n case o f o r i f i c e f l o w t h e model w i l l a l s o s w i t c h t o
f r e e o r submerged w e i r f l o w when t h e upstream water l e v e l d r o p s t o o low.
List of structures
The s t r u c t u r e s i n c l u d e d c o m p r i s e :
- pumps
- o v e r f l o w s t r u c t u r e s
- o r i f i c e s
p i p e s
- l o c a l head l o s s s t r u c t u r e s
- B a f f l e d i s t r i b u t o r s as produced by Alsthom F l u i d e s ( N e y r t e c )
S t r u c t u r e s can be p l a c e d i n s e r i e s as w e l l as p a r a l l e l . The l a t t e r a l l o w s
t h e m o d e l l i n g o f composite s t r u c t u r e s such as t h e c o m b i n a t i o n o f an
o v e r f l o w w e i r and an o r i f i c e .
Flow directionThe s t r u c t u r e parameters o f a l l s t r u c t u r e s can be g i v e n f o r b o t h p o s i t i v e
and n e g a t i v e f l o w d i r e c t i o n s w i t h r e s p e c t t o t h e c a n a l a x i s . When
s t r u c t u r e parameters a r e g i v e n f o r j u s t one f l o w d i r e c t i o n , f l o w i n t h e
r e v e r s e d i r e c t i o n i s c o n s i d e r e d zero by d e f a u l t .
Structure parameters
S t r u c t u r e parameters such as d i s c h a r g e c o e f f i c i e n t s can be v a r i e d as
f u n c t i o n o f numerous v a r i a b l e s . For example, t h e e f f e c t i v e d i s c h a r g e
c o e f f i c i e n t (Cg) o f an o v e r f l o w w e i r can be g i v e n as a f u n c t i o n o f t h e
upstream water head. I t so f o l l o w s t h a t f o r h i g h e r upstream heads t h e
w e i r w i l l s w i t c h from a broad c r e s t e d t o a sharp c r e s t e d w e i r and v i c e
Modelling the watermanagement system
Flow condition
The t r a n s i t i o n from f r e e t o submerged f l o w i s t r e a t e d i n a d i f f e r e n t way
w i t h w e i r and o r i f i c e s t r u c t u r e s . W i t h a w e i r a drowned f l o w r e d u c t i o n
c o e f f i c i e n t i s used i n c o m b i n a t i o n w i t h t h e normal f r e e o v e r f l o w stage
d i s c h a r g e r e l a t i o n . The drowned f l o w r e d u c t i o n f a c t o r v a l u e can be
s p e c i f i e d by t h e user as a f u n c t i o n o f t h e r a t i o between t h e upstream and
downstream w a t e r l e v e l . W i t h o r i f i c e s t r u c t u r e s , t h e t r a n s i t i o n between
d i f f e r e n t f l o w c o n d i t i o n s i s more c o m p l i c a t e d . Concerning f r e e f l o w an
o t h e r e q u a t i o n i s used t h a n f o r submerged f l o w and t h e o r i f i c e f l o w might
t u r n i n t o w e i r f l o w when t h e upstream head i s s u f f i c i e n t l y low. The model
d e t e r m i n e s t h e a p p l i c a b l e f l o w c o n d i t i o n , t a k i n g t h e upstream head, t h e
downstream head and t h e g a t e opening h e i g h t i n t o account. (For a more
d e t a i l e d d e s c r i p t i o n r e f e r e n c e i s made t o p a r a g r a p h 5.5, 11.2 and 12.4
o f t h i s u s e r ' s g u i d e ) .
Fortran structures
When a s t r u c t u r e cannot be d e s c r i b e d by one o f t h e s t a n d a r d s t r u c t u r e s ,
t h e user can d e f i n e t h i s s t r u c t u r e as a F o r t r a n s t r u c t u r e . I n t h a t case
t h e user has t o w r i t e a ( s h o r t ) F o r t r a n program i n which t h e d i s c h a r g e
i s d e s c r i b e d as a f u n c t i o n o f t h e upstream and downstream water l e v e l .
T h i s r o u t i n e s h o u l d be l i n k e d t o t h e package. Due t o t h e a p p l i e d
f l e x i b i l i t y i n d e f i n i n g t h e s t a n d a r d s t r u c t u r e s parameters, t h e user i s
a d v i s e d t o s e r i o u s l y c o n s i d e r t h e n e c e s s i t y o f a f o r t r a n s t r u c t u r e .
3.4 Control of regulators
I n t h e MODIS computer package s p e c i a l a t t e n t i o n was p a i d t o t h e c o n t r o l
o f r e g u l a t o r s . As a r e s u l t a l l t y p e s o f o p e r a t i o n a l t e r n a t i v e s can be
s i m u l a t e d w i t h t h e model. Both open and c l o s e d l o o p c o n t r o l can be
handled.
Open loop control
I n an open l o o p c o n t r o l system t h e o p e r a t i o n i s p r e d e f i n e d as a f u n c t i o n
o f t i m e and t h e a c t u a l s t a t e o f t h e system i s n o t c o n s i d e r e d . W i t h t h i s
User's guide MODIS
f a c i l i t y ( m a n u a l ) t i m e s c h e d u l e d c o n t r o l c a n be s i m u l a t e d .
Closed loop control
I n a c l o s e d l o o p c o n t r o l s y s t e m , c o n t r o l i s b a s e d on t h e a c t u a l s t a t e o f t h e s y s t e m . T h i s i m p l i e s t h a t t h e a c t u a l s t a t e o f t h e s y s t e m , f o r e x a m p l e a w a t e r l e v e l u p s t r e a m o f a pumping s t a t i o n , i s b e i n g r e a d by t h e c o n t r o l l e r . The c o n t r o l l e r t r a n s f o r m s t h e i n p u t v a l u e i n t o an o u t p u t s i g n a l ( F i g . 3 . 4 . 1 ) . I n t h i s way t h e pumping s t a t i o n c a n be s w i t c h e d o n / o f f d e p e n d i n g on t h e a c t u a l u p s t r e a m w a t e r l e v e l . The c o n t r o l l e r r e a d s t h e a c t u a l w a t e r l e v e l a n d t h e n d e t e r m i n e s w h e t h e r t h e pumping s t a t i o n s h o u l d b e s w i t c h e d on o r o f f . The o u t p u t s i g n a l i s p r e - d e f i n e d f u n c t i o n o f a n o t h e r v a r i a b l e . I n t h e e x a m p l e o f t h e pump, t h e d i s c h a r g e i s a p r e - d e s c r i b e d f u n c t i o n o f t h e u p s t r e a m w a t e r l e v e l , i n w h i c h t h e w a t e r l e v e l i s c a l l e d t h e f u n c t i o n v a r i a b l e . The f o l l o w i n g f u n c t i o n v a r i a b l e s a r e s t a n d a r d a v a i l a b l e i n MODIS: - u p s t r e a m w a t e r l e v e l u p s t r e a m w a t e r l e v e l head (- w a t e r l e v e l - s i l l l e v e l ) R a t i o o f t h e u p s t r e a m a n d d o w n s t r e a m head
Advanced closed loop controllers
The c o n t r o l l e r s m e n t i o n e d a b o v e , a r e p r o b a b l y t h e s i m p l e s t t y p e o f c l o s e d l o o p c o n t r o l l e r s . I n MODIS more s o p h i s t i c a t e d c l o s e d l o o p c o n t r o l l e r s h a v e b e e n i m p l e m e n t e d a s w e l l . W i t h t h e s e s o p h i s t i c a t e d c o n t r o l l e r s t h e o u t p u t v a l u e i s computed by t h e c o n t r o l l e r a n d n o t by a p r e - d e s c r i b e d f u n c t i o n . I n MODIS t h e f o l l o w i n g t y p e o f a d v a n c e d c l o s e d l o o p c o n t r o l l e r s h a v e b e e n i m p l e m e n t e d : - s t e p c o n t r o l l e r w i t h d e a d band P I D - c o n t r o l l e r w i t h s p e e d l i m i t a t i o n W i t h t h e s e a d v a n c e d c o n t r o l l e r s i t i s p o s s i b l e f o r e x a m p l e , t o s i m u l a t e t h e b e h a v i o u r o f a s y s t e m e q u i p p e d w i t h a u t o m a t i c u p s t r e a m and d o w n s t r e a m c o n t r o l l e d w a t e r l e v e l r e g u l a t o r s .
