• Aucun résultat trouvé

Ice conditions in Eastern Europe and the methods employed to influence the formation and break-up of the ice on the Dvina (Daugava) River

N/A
N/A
Protected

Academic year: 2021

Partager "Ice conditions in Eastern Europe and the methods employed to influence the formation and break-up of the ice on the Dvina (Daugava) River"

Copied!
79
0
0

Texte intégral

(1)

Publisher’s version / Version de l'éditeur:

Technical Translation (National Research Council of Canada), 1948-12-09

READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.

https://nrc-publications.canada.ca/eng/copyright

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la

première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

Questions? Contact the NRC Publications Archive team at

PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.

NRC Publications Archive

Archives des publications du CNRC

For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous.

https://doi.org/10.4224/20331607

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Ice conditions in Eastern Europe and the methods employed to

influence the formation and break-up of the ice on the Dvina (Daugava) River

Kanavins, E.

https://publications-cnrc.canada.ca/fra/droits

L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.

NRC Publications Record / Notice d'Archives des publications de CNRC: https://nrc-publications.canada.ca/eng/view/object/?id=20f7d4a5-2c7f-4272-85cd-7d2119a58dee https://publications-cnrc.canada.ca/fra/voir/objet/?id=20f7d4a5-2c7f-4272-85cd-7d2119a58dee

(2)

NATIONAL RESGARCH LABORATORIES Ottawa, Canada TSCHNICAL TRANSLATION D i v i s i o n o f Mechanical E n g i n e e r i n g Pages

-

P r e f a c e

-

4,

-

T e x t

-

4 6 F i g u r e s

-

55 T a b l e s = 4 Tech, T r a n s ,

-

TT-85 Date

-

9 December, 1 9 4 8 Lab, Order Noo 5424A F i l e

-

12-R4-22

T i t l e : E i s v e r h a e l t n i s s e i n O s t e u r o p a und d i e Angewandten Massnahmen z u r B e e i n f l u s s u n g d e r E i s b i l d u n g und d e s E i s g a n g e s i n d e r m n a (Daugava) ,

By: Edvigs Kanaving ,

J

R e f e r e n c e : Report o f the D i r e c t o r a t e of Technology and T r a n s p o r t , D i v i s i o n o f Hydrology, Riga, 1944, S u b j e c t : I C E CONDITIONS I N EASTERN 3UROPE AND T H Z METHODS

EMPLOYZD TO INFLUTNCE THE FORMATION AND BREAK-UP OF THE I C i 3 ON THE D V I N A (DAUGAVA) R I V E R ,

S u b m i t t e d by: Do B o Nazzer, T r a n s l a t e d by: S e c r e t a ~ y , D o A , S i n c l a i r , Subcommittee on S o i l

an3

Snow Mechanics, Approved by: J, H , P a r k i n ,

(3)

Page

-

( i i ) Tech, T r a n s o TT-85 PREFACE The f o l l o w i n g r e p o r t w a s p r e p a r e d a t t h e r e - q u e s t of Admiral

Dr.

h o c o

F.

S i e s s , P r e s i d e n t o f t h e German x$ Naval M e t e o r o l o g i c a l S e r v i c e s

,

f o r p r e s e n t a t i o n a t t h e con- v e n t i o n of t h e Naval ~ , ! e t e o r o l o g i c a ~ S e r v i c e s i n Hamburg,

A

s u p p l e m e n t a r y s e c t i o n i s added, s e t t i n g f o r t h a p l a n o f t h e f u t u r e programme f o r improving t h e t r o u b l e s o m e i c e c o n d i t i o n s which mere e x p e r i e n c e d on t h e Dvina H i v e r a f t e r c o n s t r u c t i o n

of t h e e l e c t r i c a l power p l a n t a t Keggum, T h i s programme h a s b e e n p r e p a r e d on t h e b a s i s of t h e o b s e r v a t i o n s d e s c r i b e d

i n t h e p r e s e n t r e p o r t a n d t h e i n v e s t i g a t i o s of t h e D e p a r t -

=f

ment of Navigable '?daterways a n d Harbours

The main p a r t of t h i s r e p o r t i s t a k e n up w i t h a d e s c r i p t i o n of t h e i n v e s t i g a t i o n of t h e i c e c o n d i t i o n s c a r r i e d o u t i n t h e w i n t e r s of 1941-42 and 1 42-43, a n d o f t h e rnethodi employed f o r r e d u c i n g t h e d e p t h i c e 2 ) i n t h e s w i f t - w a t e r s e c t i o n of t h e Dvina. I t s h o u l d n o t b e r e g a r d e d as a complete e x p o s i t i o n of t h e m a t e r i a l o r of t h e o b s e r v a t i o n s and i n v e s t i g a t i o n s , b u t m e r e l y a s an i n f o r m a t i v e s t a t e m e n t of t h e r e s u l t s o b t a i n e d and t h e u s e f u l n e s s of t h e methods employed. A f t e r t h e m a t e r i a l c o n t a i n e d i n t h e r e s e a r c h r e - s u l t s h a s b e e n e l a b o r a t e d i t i s i n t e n d e d t h a t e v e r y t h i n g s h o u l d b e made a v a i l a b l e i n a more complete p u b l i c a t i o n o

It i s a p l e a s a n t d u t y f o r t h e a u t h o r t o e x p r e s s h i s s i n c e r e a p p r e c i a t i o n t o Admiral D r , hat. F o S p i e s s and t o t h e Chief O f f i c e of Technology of L a t v i a f o r making i t pos- s i b l e f o r him t o p u b l i s h t h i s work. R i g a , 1 9 4 4 0 n) Die Deutsche S e e w a r t e . xx) D ~ p a r t e m e n t f h W a s s e r s t r a s s e n und Haf en. t ) T r a n s l a t o r f s Note : The e x p l a n a t i o n of t h i s term i s g i v e n on page 3,

(4)

Page

-

( i i i ) Techo T r a n s , TT-85 TABLE OF COITTEX'TS Page

-

P r e f a c e ( i i ) G e n e r a l Review of I c e C o n d i t i o n s on t h e R i v e r s of E a s t e r n Europe 1 The I n v e s t i g a t i o n s of t h e L a t v i a n Department of Marine on t h e Dvina up t o 1940 5 E s t i m a t e of I c e C o n d i t i o n s on t h e Dvina a f t e r C o ~ n p l e t i o n o f t h e Keggum Power P l a n t 8 I n v e s t i g a t i o n s of t h e Department of Marine on t h e Dvina i n t h e W i n t e r s of 1941-42 and 1942-43 1 5 ( a ) F o r m a t i o n of t h e I c e : The V a r i o u s Types of I c e and t h e i r P r o p e r t i e s 1 7 ( b ) The F r e e z i n g of t h e Swift-Water S e c t i o n of t h e Dvina 22

( c ) The Q u a n t i t i e s of I c e i n t h e Dvina and

t h e i r D i s t r i b u t i o n 24

( d ) Ground I c e 25

( e ) The R e d u c t i o n of t h e D r i f t I c e D r i v e n

u n d e r t h e I c e Cover ( T o s t ) 2 8

The Means Employed f o r Reducing t h e Depth

I c e 29

( a ) B o r d e r - I c e B r i d g e s 29

( b ) D r i f t I c e Dams 32

( c ) A r t i f i c i a l P r o d u c t i o n of Depth I c e 34 P o s s i b i l i t i e s of O b t a i n i n g more F a v o u r a b l e Grouping of t h e Depth I c e i n t h e Swift-Water S e c t i o n of t h e Dvina w i t h t h e Aid of I c e

(5)

Page

-

( i v )

Techo Trans TT-85

Table of Contents ( c o n t f d )

Page V I I E v a l u a t i o n of Research R e s u l t s ; Conclusions 39

V I I I The Inadequacy of t h e Previous Methods; The

Future Program f o r Improving the Troub.lesome I c e Conditions on t h e Dvina Since Completion

of t h e Keggum Power P l a n t 41

( a ) Inadequacy of t h e Maximum Program

Drawn up by the Swedish Firm 41

( b ) The Proposed I n t e r i m Program f o r Decreasing the Break-Up D i f f i c u l t i e s

on Lake Keggum 43

(6)

Page

-

1

Tech0 T r a n s , TT-85

ICE CONDITIONS I N ZASTSRN EUROPE AND THE METHODS

EMPLOYED TO INFLUENGE THX FORMATION AND

BREAK-UP OF THZ ICE ON THZ

D V I N A (DAUGAVA) RIVER

I GENERAL REVIEW OF ICE CONDITIONS ON THE RIVZRS OF EASTERN

EUROPE

Because o f t h e t r o u b l e s o m e i c e c o n d i t i o n s on t h e r i v e r s o f E a s t e r n Europe t h e d e s i g n , c o n s t r u c t i o n and o p e r a t i o n o f v a r i o u s h y d r o - e l e c t r i c a l p l a n t s i s c o n s i d e r a b l y more c o m p l i c a t e d t h a n i n t h e c o u n t r i e s o f Western Europe,

Hence, owing t o t h e i n c r e a s e d economic e x p l o i t a t i o n o f w a t e r r e s o u r c e s i n t h e e a s t e r n c o u n t r i e s , more and more a t t e n t i o n i s b e i n g p a i d t o t h i s problem, and s p e c i a l o b s e r v a t i o n s and i n v e s t i g a t i o n s a r e b e i n g u n d e r t a k e n i n o r d e r t o d i s c o v e r ways and means o f m i t i g a t i n g t h e d e s t r u c t i v e e f f e c t s o f t h e

i c e 0

The c o u r s e o f t h e phenomena i s i n g e n e r a l v e r y complex and h a s t h u s f a r been t h e o b j e c t of l i t t l e r e s e a r c h , It depends on a g r e a t many d i f f e r e n t f a c t o r s o f which t h e f o l l o w i n g a r e t h e most i m p o r t a n t : 1, C l i m a t i c f a c t o r s , which d e t e r m i n e t h e

/

l e n g t h o f t h e w i n t e r , o r i c e p e r i o d , and t h e t h i c k n e s s o f t h e i c e c o v e r ; 4 2 , G e o g r a p h i c a l f a c t o r s , i n which t h e geo- g r a p h i c a l zone and compass d i r e c t i o n o f t h e r i v e r q s c o u r s e

come u n d e r c o n s i d e r a t i o n ;

J

3. lVIorphologica1 f a c t o r s , which c h a r a c t e r i z e t h e r i v e r bed, t h e f l o w , e t c , The s e v e r i t y o f t h e i c e c o n d i t i o n s depends m a i n l y on t h e c l i m a t e , I n p l a c e s where t h e w i n t e r i s r e l a t i v e l y l o n g and s e v e r e t h e i c e c o n d i t i o n s a r e more t r o u b l e s o m e , The t h i c k n e s s o f t h e i c e c o v e r n o r m a l l y i n - c r e a s e s from s o u t h t o n o r t h , Yet i n t h e r i v e r s of E a s t e r n Europe, even i n t h e f a r n o r t h , i t d o e s n o t exceed 1 0 2 0 m e t r e s ,

It i s n o t e w o r t h y t h a t t h e i c e c o v e r i n t h e r i v e r s of S i b e r i a i s c o n s i d e r a b l y t h i c k e r t h a n t h i s ,

The g e o g r a p h i c a l s i t u n t i o n of t h e r i v e r i s c l o s e l y r e l a t e d t o t h e c l i m a t i c c o n d i t i o n s , The zone i n which it l i e s and i t s d i r e c t i o n of f l o w a r e o f g r e a t im-

(7)

Page

-

2

Tech, Trans, TT-85

portance f o r the i c e c o n d i t i o n s , I f t h e r i v e r flows from n o r t h t o south (Volga, Don, D n i e p e r ) t ) t h e p r o c e s s e s of i c e

formation and break-uptt ) f o l l o w a p e l a t i v e l y normal course.

The lower reaches of t h e r i v e r become f r e e of i c e b e f o r e t h e upper r e a c h e s , Conditions a r e a l t o g e t h e r d i f f e r e n t i f t h e r i v e r flows from s o u t h t o n o r t h (Northern Dvina, Pechora, e t c , ) , I n such r i v e r s t h e break-up u s u a l l y a t t a i n s t h e pro- p o r t i o n s of a n a t u r a l c a t a s t r o p h e , It begins, a s a r u l e , i n

t h e upper reaches of t h e r i v e r while t h e r e i s s t i l l a f i r m

i c e cover i n t h e lower ones, Immense i c e jams form which

r e s u l t i n a sudden i n c r e a s e i n the water l e v e l and d i s a s t r o u s f l o o d s , I n such c a s e s the masses of w a t e r , seeking a way around the i c e jams, demolish t h e banks, d e s t r o y s e t t l e m e n t s , t e a r open new arms of t h e r i v e r , c a r r y away sand from t h e o l d r i v e r bed, damage man-made s t r u c t u r e s ; embankments, e t c

.

I n t h e r i v e r s which flow from e a s t t o west ( ~ v i n a , Memel,

Neva, S v i r , e t c , ) t h e i c e c o n d i t i o n s may vary widely, I n c a s e s where, due t o unfavourable meteorological c o n d i t i o n s , t h e break-up begins i n t h e upper reaches of the r i v e r s p e c i a l d i f f i c u l t i e s may a r i s e which demand g r e a t e x p e n d i t u r e s of e f f o r t and m a t e r i a l on the p a r t of the a u t h o r i t i e s and or- g a n i z a t i o n s who must b a t t l e with t h e i c e ,

The morphology of t h e r i v e r i s a very important f a c t o r determining t h e n a t u r e of t h e i c e c o n d i t i o n s a t d i f - f e r e n t p o i n t s , I n p l a c e s where t h e g r a d i e n t changes suddenly, o r where t h e r i v e r t a k e s many t u r n s and i s of unequal width, o r where t h e r e a r e a g r e a t many shallow p l a c e s and i s l a n d s , dangerous i c e jams which a r e d i f f i c u l t t o e l i m i n a t e usual-ly

form during t h e break-up, I n t h e c o u n t r i e s of Western Europe,

where t h e r i v e r s a r e r e w l a t e d , t h i s circumstance i s not so

t ) T r a n s l a t o r ' s Note: I n s o f a r a s p o s s i b l e t h e s p e l l i n g of t h e geographical names has been taken from t h e Encyclopaedia B r i t a n n i c a ,

T r a n s l a t o r f s Note: Two terms a r e used

h e r e , " ~ i s a u f b r u c h " , which would r e f e r t o t h e spontaneous breaking up of t h e i c e cover i n t o f l o a t i n g masses, and "Eisgangn, d e s c r i b i n g t h e passage of t h e s e masses down-stream with t h e cur-

r e n t , Subsequently the l a t t e r term

appears t o denote both t h e s e p r o c e s s e s and t h e t r a n s l a t o r has t h e r e f o r e j u s t employed t h e one term "break-up",

(8)

Page

-

3

Tech. T r a n s , TT-85 i m p o r t a n t . I n E a s t e r n Turope, however, almost a l l t h e r i v e r s a r e s t i l l i n t h e i r n a t u r a l s t a t e , and f o r t h i s v e r y r e a s o n t h e c o u r s e of t h e i c e c o n d i t i o n s i s g r e a t l y c o m p l i c a t e d by t h e m o r p h o l o g i c a l f a c t o r s , The p r e c i p i t o u s , swif t - c u r r e n t p l a c e s i n t h e r i v e r do n o t u s u a l l y f r e e z e over. Because of

t h e f r o s t t h e w a t e r masses a t t h e open p l a c e s become s u p e r - c o o l e d and i c e b e g i n s t o c r y s t a l l i z e .through t h e e n t i r e c r o s s - s e c t i o n of t h e r i v e r from t h e s u r f a c e t o t h e bed, A c o m p l e t e l y new k i n d of i c e i s formed

-

a s o f t , s t i c k y mass of i c e w i t h a s t r u c t u r e and p r o p e r t i e s q u i t e d i f f e r e n t from t h o s e of t h e o r d i n a r y s u r f a c e i c e . Walter S p e r l i n g s u g g e s t s c a l l i n g t h e s e masses "depth i c e l l l ) ( T i e f e n e i s ) , The c u r r e n t c a r r i e s t h e s e lumps of s o f t d e p t h i c e downstream and packs them i n t o immense masses b e n e a t h t h e s o l i d i c e c o v e r i n l a y e r s which a r e s e v e r a l m e t r e s t h i c k , Thus dangerous i c e jams a r e formed, IJumerous examples, a few of which w i l l b e c i t e d , b e a r w i t n e s s t o t h e d e v a s t a t i o n s which have been caused b y i c e jams of t h i s t y p e on t h e r i v e r s of R u s s i a ,

I n t h e w i n t e r of 1902 a n i c e jam caused t h e w a t e r l e v e l i n t h e Neva t o r i s e 2 0 7 5 m e t r e s above Ordnance Datum (Germany) and a p a r t of S t o B e t e r s b u r g was f l o o d e d , S t , Pe t e r s b u r g e x p e r i e n c e d s i m i l a r f l o o d s i n t h e w i n t e r s of 1903, 1 9 1 1 and 19240

The water works i n t h a t c i t y , a l s o , have had t o contend r e p e a t e d l y w i t h c o n s i d e r a b l e d e p t h i c e d i f f i c u l t i e s D i s a s t r o u s stoppages of t h e i n t a k e c o n d u i t s o c c u r r e d , f o r

example, i n 1894 ( t w i c e ) and 1914, s o t h a t t h e e n t i r e c i t y was w i t h o u t w a t e r o The water c o n d u i t s of i n d u s t r i e s were a l s o c l o g g e d , Howevsr, t h e normal w a t e r s u p p l y of t h e c i t y

i s d i s t u r b e d b y d e p t h i c e a l m o s t every y e a r o

Depth i c e forms even i n t h e lower c o u r s e of t h e Vol;=a, Thus, i n 1925, f o r example, t h e w a t e r i n t a k e p i p e s i n Astrakhan were c l o g g e d ,

The problem of c o m b a t t i n g t h e unwelcome masses of s o f t d e p t h i c e became v e r y a c c u t e i n R u s s i a when con-

s t r u c t i o n began on t h e new h y d r o - e l e c t r i c power p l a n t s on t h e Volkhov, S v i r , Dnieper and o t h e r r i v e r s o It was d i s - covered t h a t t h e s o f t d e p t h i c e clogged t h e t w b i n e g r i d s s o t h a t o p e r a t i o n of t h e power p l a n t s had t o be e n t i r e l y s u s - ~ e n d e d ,

1) Walter S p e r l i n g : Fragen d e r X i s - , b i l d u n g und d e s Eisganges i n den F l u e s s e n , e twaige n e u e r e Erf ahrungen und G e s i c h t s p u n k t e (Problems of I c e Formation and Break-up i n R i v e r s , Some Recent d x p e r i e n c e s and A s p e c t s ) , S i x t h , , B a l t o IIydr Conf o , 1938, Report 3A, Lubeck-Berlin, 1938,

(9)

Page

-

4

Tech, Trans, TT-85

I n December, 1928, t h e s e v e r a l hundred s q u a r e metre g r i d s t r u c t u r e of t h e t u r b i n e s i n t h e Volkhov Hydro- e l e c t r i c S t a t i o n was covered w i t h a s o f t l a y e r of i c e approxi-

mately one metre t h i c k , The t o t a l weight of t h e s e i c e masses

was several hundred t o n s , The i c e was f r o z e n s o hard t o t h e g r i d s t h a t when a t t e m p t s were made t o d i s l o d g e it w i t h c r a n e s t h e 25 m, s t e e l c a b l e s broke l i k e p i e c e s of twine, The

g r i d s could o n l y be c l e a n e d by d i v e r s , a f t e r which t h e y were r a i s e d , h e a t e d w i t h h o t w a t e r , and r e p l a c e d , A l l t h i s was

of no a v a i l , t h e g r i d s were soon clogged a g a i n , Twenty-five

d i v e r s had t h u s worked f o r f i v e days t o no purpose, It was n o t u n t i l a r a t h e r l o n g s t r e t c h of t h e Volkhov had been f r o z e n over t h a t t h e masses of s o f t d e p t h i c e vanished and t h e o p e r a t i o n o f t h e power p l a n t c o u l d be resumedo

C o n s i d e r a b l e d e p t h i c e d i f f i c u l t i e s b e s e t o t h e r power p l a n t s i n R u s s i a , Many of them a r e o b l i g e d t o suspend o p e r a t i o n f o r weeks a t a time, t h u s s u s t a i n i n g g r e a t l o s s e s , T h i s happens almost e v e r y y e a r ,

I n g e n e r a l t h e e f f e c t of t h e i c e on hydro- e l e c t r i c i n s t a l l a t i o n s i s shown i n t h e f o l l o w i n g ways:

1, S t a t i c a l l y

-

due t o p r e s s u r e from t h e expansion of t h e i c e o r due t o f r e e z i n g and f l u c t u a t i o n s of t h e w a t e r l e v e l ;

2 , Dynamically

-

d u r i n g t h e break-up;

3 , By becoming clogged w i t h d e p t h i c e ,

The s t a t i c e f f e c t may be avoided f a i r l y e a s i l y b:y b r e a k i n g up t h e i c e , The dynamic e f f e c t d u r i n g t h e b r e a k - up can a l s o be m i t i g a t e d t o a c o n s i d e r a b l e e x t e n t by b r e a k i n g up t h e i c e c o v e r ahead of time and r e d u c i n g t h e s i z e o f t h e lumps, Various d e f e n c e s may a l s o be e r e c t e d a g a i n s t b o t h of t h e s e e f f e c t s o However, no e f f e c t i v e remedy h a s a s y e t been found f o r t h e o b s t r u c t i o n s and c l o g g i n g s caused by t h e d e p t h i c e e

The f o l l o w i n g q u o t a t i o n from t h e p e r i o d i c a l , " E l a c t r o - ~ n e r g e t i c s i n S o v i e t Russia", w i l l I l l u s t r a t e t h e

d i f f i c u l t i e s accompanying t h e s t r u g g l e a g a i n s t t h e i c e i n E a s t e r n Europe and t h e means r e q u i r e d t o d e a l w i t h them:

he

o f f i c i a l l o s s c o e f f i c i e n t f o r each i d l e k i l o w a t t hour i s f o u r r u b l e s , The stoppage of a power p l a n t of 100,000 k w , o u t p u t means a l o s s t o i n d u s t r y o f 400,000

(10)

Page

-

5

Tech, Trnns, TT-85 r u b l e s p e r h o u r , A one.-day work stoppage a t t h e Kusnetsny M e t a l l u r g i c a l P l a n t due t o c l o g g i n g of t h e w a t e r i n t a k e would c o s t t h e p l a n t 10,000,000 rublest!

I n view of t h e s e d i f f i c u l t i e s a d d i s t u r b a n c e s i n t h e Russian power p l a n t s t h e S t a t e Hydrological I n s t i t u t e i n Leningrad was i n s t r u c t e d t o c a r r y out r e s e a r c h e s f o r

s e v e r a l y e a r s b o t h i n t h e l a b o r a t o r y and on t h e .m.~lkhov, S v i r , Neva, Volga, Dnieper and o t h e r r i v e r s ,

The r e s u l t s of t h e o b s e r v a t i o n s and r e s e a r c h appeared i n t h e f o l l o w i n g Russian p u b l i c a t i o n s : "Reports

of t h e S t a t e H y d r o l o g i c a l I n s t i t u t e " , " ~ e p o r t s of t h e I n s t i t u t e f o r S c i e n t i f i c Research i n t h e F i e l d of Hydraulicay "The

Volkhov, S v i r and Dnisper River Development P r o j e c t s n and i n many p e r i o d i c a l s , The f o l l o w i n g s h o u l d be mentioned a s more

e x t e n s i v e , s i n g l e works: P r o f , Wi , J , A l t b e r g , "Depth I c e w ,

Leningrad, 1939 ; I n g ,

F,

J , Bydin, "Combatting t h e Break-up

on t h e S v i r R v e r " , Leningrad, 1934; BOP, Weinberg, "Ice!

f

Moscow, 19402

,

Concerning t h e d.egree of s u c c e s s i n t h e

s t r u g g l e a g a i n s t t h e i c e i n Russia t h e judgmant of Ing, FoJo Bydin, g i v e n d u r i n g h i s v i s i t t o Riga i n t h e s p r i n g of 1940 t o observe and a s s e s s t h e i c e c o n d i t i o n s on t h e Dvina, may be quoted:

"Valuable o b s e r v a t i o n and r e s e a r c h d a t a con- c e r n i n g t h e r i v e r s of R u s s i a have been c o l l e c t e d , '~Vithout t h i s informat i o n new hydro- t e c h n i c a l s t r u c t u r e s c o u l d n e i t h e r be planned n o r b u i l t o S u i t a b l e means of combatting t h e d e p t h

i c e , however, have s t i l l t o be found, I f , i n t h i s o r t h a t i n s t a n c e , t h e means d i s c o v e r e d and employed have proved s u c c e s s f u l , t h e r e i s s t i l l no j u s t i f i c a t i o n f o r r e g a r d i n g t h e s e a s a b s o l u t e l y s u r e i n a l l c a s e s , a s i s proved i n a s e r i e s of c o n c r e t e , p r a c t i c a l a p p l i c a t i o n s , The complex d e p t h i c e p r o c e s s e s must s t i l l be i n v e s t i g a t e d c a r e f u l l y and f o l l o w e d up," THE D V I N A UP TO 1940

-

.- Before b e g i n n i n a a d e s c r i ~ t i o n of t h e in- e d a t a w i l l f i r s t be on t h e Dvina i t - W, J, A l t b e r g : Podvodny Lyod, Leningrad, 1939, F,T, Bydin: S v i r s t r o y (Borba so lyodom) Leningrad, 1934, BOP, Wsinbsrg:Lyod, Moscow, 1940,

(11)

Page

-

6

Tech, T r a n s , TT-85

s e l f t o g e t h e r w i t h i n f o r m a t i o n about t h e o b s e r v a t i o n s and i n v e s t i g a t i o n s made i n former y e a r s ,

The Dvina 1s one of t h e l a r g e s t r i v e r s on t h e B a l t i c c o a s t , It r i s e s i n t h e C e n t r a l Russian Highland

( V a l d a i ~ i g h l a n d ) , flows t h r o u g h t h e White Russian S o R o and L a t v i a , d r a i n i n g a n a r e a of 82,800 s q u a r e k i l o m e t r e s , A f t e r t r a v e r s i n g a c o u r s e of 1000 k f l o m e t r e s i t empties i n t o t h e Gulf of Riga, For c e n t u r i e s i t has s e r v e d a s an i m p o r t a n t e a s t - w e s t waterway,

I n t h e s t r e t c h from J a k o b s t a d t t o I n s e l Dahlen

-

190 and 25 km, from t h e mouth r e s p e c t i v e l y

-

t h e Dvina i s v e r y t u r b u l e n t and has dug i t s bed deep i n t o t h e Devonian d o l o m i t e , A t many p o f n t s the f o l d s and bends i n t h e dolomite form g r e a t r a p i d s , and t h i s s t r e t c h i s t h u s known a s t h e " s w i f t w a t e r s e c t i o n " of t h e Dvina, Over t h t s s t r e t c h , which i s a p p r o x f n a t e l y 160 k i l o m e t r e s l o n g , t h e mean w a t e r l e v e l of t h e Dvina drops 80 m e t r e s , f o e o , an average of 50 c e n t i m e t r e s p e r r u n n i n g k i l o m e t r e , I n c e r t a i n s e c t i o n s , e , g , , o v e r t h e 1 5 k f l o m e t r e s from Stockmannshof t o Kokenhusen, t h e g r a d i e n t a c t u a l l y becomes a s g r e a t a s one metre p e r k i l o - m e t r e , F i g u r e 1 g i v e s t h e l o n g i t u d i n a l p r o f i l e of t h e s w i f t w a t e r s e c t i o n of t h e Dvfna, and F i g u r e s 2 and 3 show t h e most important r a p i d s ,

The r a p i d s of t h e Dvina may be p u t t o advan- t a g e o u s use i n t h e p r o d u c t i o n of h y d r o - e l e c t r i c energy,

According t o t h e L a t v i a n e l e c t r i f f c a t i o n p l a n , s t a r t i n g w i t h t h e y e a r 1933, t h e Dvfna i s t o be d f v f d e d i n t o s i x develop- ment s t a g e s w i t h drops r a n g f n g from 7025 t o 17,O m e t r e s , With t h e r e a l i z a t i o n of t h i s p l a n t h e w a t e r power of t h e

Dvina would be f u l l y e x p l o i t e d , y i e l d i n g a n o u t p u t of 300,000

k f l o w a t t s semf-annually, A t t h e same tfme t h e Dvina would

become an e x c e l l e n t waterway f o r b o a t s of t h r e e m e t r e s d r a u g h t ,

3

One of t h e s e s t a g e s was completed i n 1939 The dam of t h e Keggum power p l a n t was b u i l t i n t h e c e n t r a l p a r t of t h e s w i f t - w a t e r s e c t i o n of t h e Dvina 65 k f l o m e t r e s above t h e mouth, c r e a t i n g a c o n c e n t r a t e d drop of 15,75

metres. The mark of t h e dammed up w a t e r l e v e l i s 32 m e t r e s above s e a l e v e l , A t t h i s l e v e l a l a r g e dam b a s i n , t h e so- c a l l e d "Lake ~ e g g u m * , i s formed above t h e dam, I t i s 45

25 s q u a r e k f l o m e t r e s , Kraftwerk Kegums (The Keggum Power

P l a n t of L a t v i a ) , Z, W a s s e r k r a f t und W a s s e r w i r t s c h a f t , 1938,

(12)

Page

-

7

Tech, Trans, TT-85 S i n c e t h e r e a r e a number of s e t t l e m e n t s i n t h e a r t i f i c i a l l a k e r e g i o n i t was decided t o p r o t e c t them by means of em- bankments, The l a r g e s t of t h e s e , b u i l t t o p r o t e c t t h e c i t y of F r i e d r i c h s t a d t , i s 3,4 k i l o m e t r e s i n l e n g t h and i n p l a c e s a t t a i n s a h e i g h t of 5 m e t r e s , The h e i g h t of t h e embankments was determined from o b s e r v a t i o n s of t h e w a t e r l e v e l d u r i n g

t h e unusual f l o o d i n t h e s p r i n g of 1931, when t h e flow of water i n t h e Dvina reached 9000 c u b i c metres p e r second,

As i n t h e o t h e r r i v e r s of E a s t e r n Europe t h e troublesome i c e c o n d i t i o n s i n t h e Dvina a l s o c r e a t e con-

s i d e r a b l e d i f f i c u l t i e s , I n working o u t t h e Dvina development p r o j e c t t h e q u e s t i o n of t h e t y p e and q u a n t i t y of i c e accumu- l a t i n g i n t h e Dvina d u r i n g t h e w i n t e r months,and t h e r e f o r e t o be c o n s i d e r e d d u r i n g t h e break-up, a r o s e , The i d e a was even e x p r e s s e d t h a t t h e s o f t masses of d e p t h i c e might a l s o l e a d t o dangerous c l o g g i n g s i n t b newly c o n s t r u c t e d power p l a n t s , a s s u g g e s t e d by t h e e x p e r i e n c e s i n R u s s i a ,

I n t h i s c o n n e c t i o n t h e Department of Marine made t h e f i r s t measurements of t h e q u a n t i t i e s of i c e i n t h e Dvina i n t h e w i n t e r of 1931-32, a t t h e same time c l a s s i f y i n g

t h e d i f f e r e n t t y p e s , T h i s was done over a 250 k f l o m e t r e s t r e t c h

of t h e r i v e r , from Daugavpils (Dvinsk) t o I n s e l Dahlen, The

measurements l e d t o a s u r p r i s i n g r e s u l t , It was found t h a t i n t h e s w i f t - w a t e r s e c t i o n of t h e r i v e r , over t h e 90 k i l o m e t r e s t r e t c h from Kokenhusen t o I n s e l Dahlen, t h e t o t a l I c e masses

came t o 43,000,000 cubfc m e t r e s , o r an average of 478,000 c u b i c

metres f o r each r u n n i n g k i l o m e t r e , and of t h i s amount t h e s o f t masses of depth i c e packed under t h e i c e cover accounted f o p

approximately 70 p e r c e n t , I n t h e remaining s e c t i o n of t h e r i v e r , from J a k o b s t a d t t o Daugavpils, o n l y t h e h a r d s u r f a c e i c e was found, averaging approximately 100,000 c u b i c m e t r e s p e r r u n n i n g k i l o m e t r e ,

To advance t h e r e s e a r c h i n t o d i f f i c u l t i c e c o n d i t i o n s and t o l e a r n how i c e i s r a t e d abroad and what defence measures a r e t a k e n f n o t h e r c o u n t r i e s i n t h e d e s i g n and c o n s t r u c t i o n of h y d r a u l i c s works, t h e Department of Marine f u r i s h e d a s p e c i a l r e p o r t on t h e i c e c o n d i t i o n s on t h e Dvina4P t o t h e F o u r t h H y d r o l o g i c a l Conference of the B a l t i c S t a t e s i n Leningrad i n 19330 U n f o r t u n a t e l y t h e pro- blem was n o t c l a r i f i e d a t the c o n f e r e n c e o

When t h e Dvina development was begun t h e l e t t l a e n d i s c h e n F l u e s s e , insbesondere

d e r D h a ( ~ a u g a v a )

in he

I c e C o n d i t i o n s on L a t v i a n R i v e r s , E s p e c i a l l y t h e

~ v i n a ) , 4 t h B a l t , Hydr, Conf,, Lenin- g r a d , 1933,

(13)

Page

-

8

Tech, Trans, TT-85

i c e c o n d i t i o n s i n t h e h y d r o l o g i c a l s e c t i o n o f t h e I n t e r -

n a t i o n a l Union of Geodesy and Geophysics Union i n t e r n a t i o n a l e

f

de GBodBsie e t ~ Q o p h y s i q u e ) i n Edinburgh5

.

The Russians

a l s o s u b m i t t e d a s i m i l a r r e p o r t t o t h i s c o n f e r e n c e on t h e troublesome i c e c o n d i t i o n s on t h e i r r i v e r s , The problem a g a i n remained u n c l a r i f i e d ,

I n 1938 a t t h e S i x t h H y d r o l o g i c a l Conference o f t h e B a l t i c s t a t e s i n ~ n b e c k and B e r l i n p a r t i c u l a r a t t e n - t i o n was p a i d t o t h e problem o f i c e c o n d i t i o n s , Germany, Norway, Sweden and Poland s u b m i t t e d r e p o r t s on t h e i r r e s e a r c h r e s u l t s i n t h i s f i e l d , b u t u n f o r t u n a t e l y no c o n c l u s i o n s were reached on t h i s o c c a s i o n , e i t h e r , Regarding t h e problem of i c e f o r m a t i o n and break-up f n t h e r i v e r s , t o g e t h e r w i t h c e r - t a l n r e c e n t e x p e r i e n c e s and p o i n t s of view i n t h i s c o n n e c t i o n , t h e f o l l o w i n g s t a t e m e n t was a l l t h a t ensued: "No formal

c o n c l u s i o n was r e a c h e d on t h i s p o i n t of t h e agenda, However, g r e a t v a l u e i s p l a c e d on a n i n t e r n a t i o n a l exchange o f o b s e r - v a t i o n s and experiences.'

The Department of Marine complied w i t h t h e s u g g e s t i o n i m p l i e d i n t h i s s t a t e m e n t and c o n t i n u e d t o c o l l e c t d a t a on t h e i c e c o n d i t i o n s from y e a r t o y e a r , f o r t h e

e x p e r i e n c e s c l e a r l y showed t h a t t h e r e s u l t s of s u c h i n v e a t i - g a t i o n s would be v e r y v a l u a b l e i n solving v a r i o u s problems connected w i t h t h e economics of w a t e r r e s o u r c e s ,

I11 ESTIMATE OF I C E CONDITIONS ON THE DVINA AFTER COMPLETION OF

THE

KEGGUM POWER PLANT

When t h e Swedish f i r m , A k t i e b o l a g e t

Vattenbyggnadsbyrbn ( V B B ) , began work on t h e Keggum power

p l a n t , i t s o f f i c i a l s c a r e f u l l y examined t h e o b s e r v a t i o n and r e s e a r c h r e s u l t s of t h e Department of Marine from p r e v i o u s y e a r s and made themselves t h o r o u g h l y a c q u a i n t e d w i t h t h e i c e c o n d i t i o n s on t h e Dvina by on-the-spot i n v e s t i g a t i o n s o

The most complete e s t i m a t e .of t h e i c e con- d i t i o n s on t h e Dvina i s f u r n i s h e d by t h e c o n s u l t a t i v e memo- randa s u b m i t t e d by t h i s Swedish f i m ( V B B ) , which t h e Depart- ment of Marine has o b t a i n e d from t h e Power P l a n t D i v i s i o n

of t h e B a l t i c Power Supply Company, Ltdo (Energieversorgung Ostland, G o m, b,

H,),

The a u t h o r h a s t a k e n t h e l i b e r t y o f

t h e R i v e r s of L a t v i a , Cons, I n t o d o Unions Sc i e n t i f i q u e s , B u l l e t i n No, 23, 1936,

(14)

Page

-

9

Tech, T r a n s , TT-85 Memorandum of 1 2 November 1935 (Re e x p e c t e d i c e c o n d i t i o n s on the Dvina a f t e r completion o f t h e Keggum Power P l a n t ) :

"The well-known s t u d i e s p u b l i s h e d b y Obering P o S t a k l e on t h e q u e s t i o n of how t h e i c e c o n d i t i o n s on t h e Dvina behave i n d i f f e r e n t y e a r s and a t d i f f e r e n t s e a s o n s a r e v e r y e n l i g h t e n i n g , It would p r o b a b l y be impossible t o d i s - c o v e r dependable p r i n c i p l e s f o r a s s e s s i n g t h e immediate pro- blem on t h e b a s i s of o b s e r v a t i o n s made on t h e Dvina a l o n e . We v a l u e t h e panoramic p i c t u r e a f f o r d e d by t h e s e s t u d i e s a l l

t h e more h i g h l y because it e n a b l e s u s t o draw c e r t a i n con- c l u s i o n s , by comparison w i t h o t h e r r i v e r s , c o n c e r n i n g t h e form which t h e i c e c o n d i t i o n s may be e x p e c t e d t o t a k e i n t h e Dvina f o l l o w i n g completion o f t h e power p l a n t , It i s be- l i e v e d t h a t t h e Russian r i v e r s , Volkhov and S v i r , may p r o v i d e a s u i t a b l e b a s i s f o r t h i s comparison,''

A b r i e f comparison of t h e two Russian r i v e r s

w i t h t h e Dvina f o l l o w s , t o g e t h e r w i t h a more d e t a i l e d des- c r i p t i o n of t h e changes which t o o k p l a c e i n t h e i c e c o n d i t i o n s on t h e Volkhov and S v i r f o l l o w i n g c o m p l e t i o n of t h e Volkhov and S v i r power p r o j e c t s , A t t h e end of t h e memorandum t h e f o l l o w i n g c o n c l u s i o n i s s t a t e d :

"It may b e f o r e s e e n t h a t t h e b u i l d i n g of t h e dam a t Keggum w i l l b r i n g about a c o n s i d e r a b l e improvement i n t h e i c e c o n d i t i o n s i n t h e lower p a r t of t h e Dvina. The pro- s p e c t s of a n improvement downstream from t h e power i n s t a l - l a t i o n seem p a r t i c u l a r l y good i n view of t h e f a c t t h a t t h e l a r g e dam b a s i n , whose e x t e n t and volume a r e comparable t o t h o s e of t h e t w o Russian examples which have been c i t e d , w i l l

r e t a i n l a r g e ' q u a n t i t i e s of d r i f t i c e ( ~ r e i b e i s ) and cause them t o thaw, It should a l s o be remembered t h a t t h e p r e s e n c e of a d j u s t a b l e s l u i c e g a t e s w i l l permit a c e r t a i n r e g u l a t i o n of t h e water l e v e l , o r of t h e q u a n t i t i e s of w a t e r and i c e

f l o w i n g downstream,

"The o n l y r e g i o n where some u n c e r t a i n t y may s t i l l be s a i d t o e x i s t a p p e a r s t o be t h e t r a n s i t i o n a l r e g i o n between t h e dam b a s i n and the undammed s e c t i o n of t h e r i v e r , However, t h e a n x i e t y we f e e l i n c o n n e c t i o n w i t h t h i s r e g i o n i s i n c o n t r a d i c t i o n t o a l l t h e o b s e r v a t i o n s on t h e Volkhov and Svirjl Memorandum of 1 6 February 1939 ( R e e x p e c t e d i c e c o n d i t i o n s a f t e r complstion of t h e dam b a s i n ) : "During c u r r e n t d i s c u s s i o n s on t h e p r o j e c t i n

(15)

Page

-

1 0

Tech, Trans. TT-85

planning t o a t t e n d t h e world conference on power production i n America i n 1936, should make t h e problems i n q u e s t i o n t h e o b j e c t of a s p e c i a l s t u d y , This p l a n was a c t u a l l y put i n t o e f f e c t , a s e r i s s of problems was formulated and t h e journeys were undertaken, Unfortunately i t turned out t h a t t h e ex- p e r i e n c e s of America were of l i t t l e value f o r t h e Keggum c a s e , s i n c e t h e i c e problems t h e r e a r e a l t o g e t h e r . d i f f e r e n t ,

"We a l s o t r i e d t o make use of experiences

elsewhere, e.g,, on t h e Danube and on c e r t a i n Russian r i v e r s , One of our e n g i n e e r s made a s p e c i a l t r i p f o r t h i s purpose t o Donau-Kachler and o t h e r p l a c e s t o i n v e s t i g a t e t h e i c e con-

d i t ions t h e r e , The a v a i l a b l e d a t a , however, were i n s u f f i c i e n t t o provide a f i n a l s o l u t i o n t o t h e problem, e s p e c i a l l y w i t h regard t o t h e i c e c o n d i t i o n s up-stream from t h e dam b a s i n , Thus t h e r e remains only one p o s s i b i l i t y of a s s e s s i n g t h i s problem c o n s t r u c t i v e l y , namely b y u t i l i z i n g t h e experiences on t h e Dvina i t s e l f a s described by D i r e c t o r P, S t a k l e , I n the following, t h e r s f o r e , a t r a i n of thought has been de- veloped, w i t h a view t o d i s c o v e r i n g ways and means of s e t t i n g up t h e d e s i r e d maximum programme f o r combatting t h e i c e .

"According t o S t a k l e t h e i c e season i s

divided i n t o t h r e e more o r l e s s d i s t i n c t p e r i o d s , namely:

1, Formation of d r i f t i c e ( ~ r e i b e i s ) ,

2 , Formation of s u r f a c e i c e .

3. The break-up,

he

break-up i s of d e c i s i v e importance i n determining t h e methods t o be employed i n combatting t h e i c e on t h e dam b a s i n . Considerable p i l i n g up of t h e i c e has

a l r e a d y occurred on previous occasions under n a t u r a l c o n d i t i o n s a t t h e p l a c e i n q u e s t i o n , i b e , , i n t h e v i c i n i t y of F r i e d r i c h - s t a d t . Since d u r i n g t h e break-up l a r g e q u a n t i t i e s of i c e must be t r a n s p o r t e d i n a s h o r t time from t h e undammed s e c t i o n

of t h e r i v e r i n t o t h e shallow water of t h e dam b a s i n , and s i n c e t h i s must be done a t a time when t h e a r t i f i c i a l l a k e

i s expected t o be covered w i t h a r e l a t i v e l y t h i c k l a y e r of i c e , it i s n o t improbable t h a t t h e break-up t r o u b l e s a f t e r t h e dam has been put i n t o o p e r a t i o n w i l l assume a t l e a s t t h e same p r o p o r t i o n s i n some years a s formerly, u n l e s s s u f f i c i e n t room f o r the in-coming i c e masses w i t h i n t h e dam b a s i n is provided,

(16)

Page

-

11

Tech, T r a n s , TT-85 "On t h e o t h e r hand, i t s h o u l d be n o t e d t h a t by s u i t a b l e employment of t h e dam b a s i n f o r t h e accommodation of t h e incoming masses of i c e t h e p o s s i b f l i t y i s g a i n e d of r e d u c i n g , i f n o t a l t o g e t h e r e l i m i n a t i n g , t h e break-up d i f - f i c u l t i e s , T h i s i s v a l u a b l e , s i n c e t h e r e q u i r e d measures which would be d e t r i m e n t a l t o t h e economic o p e r a t i o n of t h e power p l a n t , p e r m i t p a r t of t h e c o s t s t o be t r a n s f e r r e d t o a g r i c u l t u r e

,

"The f o l l o w i n g temporary programme may be s e t up f o r d e c r e a s i n g t h e d i f f i c u l t i e s which accompany t h e break-up :

1, Observation of t h e i c e regime above t h e dam

b a s i n throughout t h e e n t i r e w i n t e r ;

2 , A n t i c i p a t i o n of t h e break-up as a c c u r a t e l y a s p o s s i b l e by means of weather p r e d i c t i o n ;

3, Breaking up of t h e i c e c o v e r o v e r a s u f f i c i e n t l y l a r g e s e c t i o n o f t h e upper p a r t of t h e dam b a s i n soon enough b e f o r e t h e break-up; p r e v e n t i o n of t h e f o r m a t i o n o f a new

i c e c o v e r ;

4 , Reduction of t h e l e v e l a t t h e dam t o one metre immediately b e f o r e t h e break-up;

5 0 Release of any f l o o d wave which may occur due t o t h e break-up t h r o u g h t h e dam b a s i n and t h e w e i r ; a c c o m o d a t i o n o f t h e i c e flow i n t h e dam b a s i n , and, where n e c e s s a r y , i t s

i n t e r m i t t e n t r e l e a s e t h r o u g h t h e w e i r , c h i e f l y by employing t h e 80 metre s l u i c e g a t e s ,

11 According t o p r e v i o u s e x p e r i a n c e t h e o n l y way t o e n s u r e t h e c r e a t i o n and maintenance o f a s u f f i c i e n t l y l a r g e opening i n t,he i c e c o v e r of t h e dam b a s i n i s t o b r e a k

i t up w i t h i c e - b r e a k e r s , These have a l r e a d y been employed s u c c e s s f u l l y on t h e Dvina (Riga Harbour) a s w e l l a s on o t h e r L a t v i a n r i v e r s . It would be s t i l l b e t t e r i f t h e i c e - b r e a k e r s c o u l d be combined w i t h t h e t u g b o a t s which a r e needed i n any c a s e f o r t h e l o g g i n g i n d u s t r y *

"The above r e p r e s e n t s a maximum programme f o r combatting t h e i c e break-up and may b e m o d i f i e d , of c o u r s e , i n accordance w i t h e x p e r i e n c e g a i n e d from a c t u a l l y p u t t i n g i t i n t o e f f e c t , I n f a v o u r a b l e y e a r s , i t may be c o n s i d e r a b l y c u r t a i l e d , I n t h i s c o n n e c t i o n t h e most important q u e s t i o n i s t o what e x t e n t it i s n e c e s s a r y t o b r e a k up t h e i c e c o v e r

(17)

Page

-

12

Tech, Trans. TT.85

i n t h e most unfavourable case which may be f o r e s e e n , This

problem may be c l a r i f i e d t o some e x t e n t by comparing t h e volwne of t h e dam b a s i n w i t h t h a t of the s t o r e d up masses of

i c e i n t h e r i v e r , The e n t i r e d m b a s i n has a volume of from 100 t o 150 m i l l i o n cubic metres, of which t h e upper 20 k i l o - metres a t most account f o r only 20 p e r c e n t , O n t h e 90

kilometre s t r e t c h from t h e 35 t o 125 kilometre marks, a

s t o r e d up i c e mass was measured i n t h e w i n t e r of 1931/32 averaging no l e s s than 500,000 cubic metres p e r k i l o m e t r e ,

More

d e t a i l e d r e s e a r c h r e s u l t s on t h i s m a t t e r f o r t h e s t r e t c h above t h e dam b a s i n a r e not a v a i l a b l e , Judging from S t a k l e P s d a t a t h e amount of s t o r e d up i c e i n t h i a r e - gion i s expected t o be c o n s i d e r a b l y l e s s t h a n t h a t s t a t e d above, b u t w i l l be l a r g e enough t o make i t appear a d v i s a b l e t o proceed w i t h c a u t i o n d u r i n g t h e f i r s t y e a r , so t h a t un- f o r t u n a t e experiences r e s u l t i n g from inadequate means may be avoided, -It w i l l be b e s t t o have t h e maximum e x t e n t of t h e expected break-up a s s e s s e d and e s t i m a t e d by t h e Latvian o f f i c i a l s

,

" I n most y e a r s i t should be n e c e s s a r y t o break only a r e l a t i v e l y s m a l l a r e a of the i c e cover, Even i f , f o r t h e p r e s e n t , an i c e break-up amounting t o 6,000,000 cubic metres p e r 30 kilometre s t r e t c h and 200,000 cubic metres of i c e p e r kilometre be assumed, i n a l l p r o b a b i l i t y

t h e b r e a k i n g of tho i c e cover over a s t r e t c h of s e v e r a l k i l o m e t r e s upstream and downstream from F r i e d r i c h s t a d t would be s u f f i c i e n t f o r t r i a l purposes d u r i n g the f i r s t y e a r s of o p e r a t i o n , I n any c a s e t h e f l o o d i n g of

F r i e d r i c h s t a d t under such circumstances appears impossible, s i n c e t h e flow opening beneath t h e i c e cover i n t h e r i v e r i s approximately s i x metres,

"Attention must a l s o be p a i d t o t h e o t h e r w i n t e r p e r i o d s , p a r t i c u l a r l y t o t h a t of d r i f t i c e formation, The i c e forming process above t h e dam b a s i n should be

s i m i l a r t o t h a t i n t h e Dvina above t h e Riga b r i d g e s , It i s q u i t e p o s s i b l e t h a t the d r i f t i c e may cause i c e jams a t t h e upper end of t h e dam b a s i n a f t e r t h e s u r f a c e i c e cover has formed on t h e a r t i f i c i a l l a k e , It i s n o t expected, how- e v e r , t h a t t h e s e w i l l be g r e a t e r than was formerly t h e case i n t h e n a t u r a l course of t h e r i v e r . A l l experiences i n d i c a t e t h a t c o n d i t i o n s . f n t h i s r e s p e c t w i l l be more favourable a f t e r t h e c o n s t r u c t i o n of t h e dam than b e f o r e ,

"The i c e b r e a k e r s mentioned i n connection with t h e programme f o r combatting the break-up may be used a l s o t o m i t i g a t e t h e i c e d i f f i c u l t i e s d u r i n g the p e r i o d of

(18)

Page 13

Tech, Trans, TT-85 f o r m a t i o n of d r i f t f ce, by h a v i n g them c u t an opening i n

t h e i c e cover of t h e a r t i f i c i a l l a k e f o r t h e incoming i c e , so t h a t an i c e b a r cannot form,

"With r e g a r d t o t h e s e c t i o n of t h e r i v e r below t h e power p l a n t , f t i s q u i t e p o s s i b l e t h a t t h e f o r m a t i o n of d r i f t i c e and t h e l o c a l i c e jams, owing t o &he d a i l y r e g u l a t i o n s , w i l l assume somewhat l a r g e r p r o p o r t i o n s , On t h e o t h e r hand t h e f l u c t u a t i o n s i n t h e water l e v e l may h i n d e r t h e g a t h e r i n g of i c e , s o t h a t t h e d i f f i c u l t i e s due

t o p i l i n g up, e t c . , b e d e c r e a s e d . Furthermore i t can be e x p e c t e d ( c f , above t h a t t h e i n f l u x of t h e break-up from t h e upper s e c t i o n may be compensated, i f n o t wholly avoided, by means of the a r t i f i c i a l l a k e , "

I n t h e w i n t e r of 1940 t h e c o n s t r u c t i o n a l work on t h e power p l a n t was n e a r i n g completion; among o t h e r t h i n g s , however, t h e s l u i c e g a t e s f o r t h e t r a n s m i s s i o n of i c e and f l o o d w a t e r were n o t y e t f t n i s h e d , I n t h i s c o n n e c t i o n t h e

Swedish f i r m , Svenska E n t r e p r e n a d A k t i e b o l a g e t ( S e n t a b )

,

which was i n charge of c o n s t r u c t i o n on t h e Keggum power p l a n t , had i t s e l f worked o u t a p l a n f o r t h e t r a n s m i s s i o n of f l o o d water and i c e through t h e w e i r , and t h i s had been recommended and a c c e p t e d i n c o n s u l t a t i o n w i t h t h e Keggum b u i l d i n g i n s p e c t i o n a u t h o r i t i e s and t h e S t a t e E l e c t r i c a l Power Corporation*

(VEU)

of Keggum, A d e t a i l e d d i s c u s s i o n of t h i s p l a n would l e a d t o o f a r a f i e l d ,

I t need o n l y be mentioned t h a t a t t h e s u g g e s t i o n of t h e Department of Marine, t o e n s u r e t h a t t h e i c e masses would be conducted i n t o t h e a r t i r i c i a l l a k e , dynamiting of t h e i c e cover was c a r r i e d o u t i n t h e v i c i n i t y of F r i e d - r i c h s t a d t between 2 3 , 5 and 31 k i l o m e t r e s up-stream from t h e dam, t h u s opening a channel of s i n g l e h o l e s 7,5 k i l o - m e t r e s l o n g and 50 m e t r e s wide, T h i s was i n t e n d e d t o r e p l a c e t h e b r e a k i n g of t h e i c e cover by t h e i c e b r e a k e r s p r e v i o u s l y mentioned i n c o n n e c t i o n w i t h t h e maximum program of t h e VBB f i r m ,

T h i s w e l l c o n s i d e r e d method was s u c c e s s f u l i n t h e y e a r 1940, a l t h o u g h t h e water l e v e l d u r i n g t h e i n f l u x of t h e i c e masses i n t o t h e dam b a s i n was c o n s i d e r a b l y h i g h e r t h a n e x p e c t e d , so t h a t t h e upper s u r f a c e of t h e newly c o n s t r u c t e d embankment was o n l y a few d e c i m e t r e s above t h e s u r f a c e of t h e w a t e r , The p r e v i o u s dynamiting had n o t produced t h e expected a l l e v i a t i o n s t o t h e e x t e n t d e s i r e d ,

(19)

Page 14

Tech. T r a n s . TT-85

On t h e b a s i s o f t h e o b s e r v a t i o n s and e x p e r i e n c e s d u r i n g t h e b r e a k - u p o f 1940 t h e VBB s u p p l e m e n t e d i t s

nenorandum of t h e 16 F e b r u a r y 1339 w i t h t h e f o l l o w i n g : "~ernorandum of t h e 25 November 1340 (He i c e c o n d i t i o n s a f t e r c o n s t r u c t i o n o f t h e dam):

" I n o u r Memorandum o f t h e 1 6 ' F e b r u a r y 1939 and i n s u b s e q u e n t c o r r e s p o n d e n c e c e r t a i n p r i n c i p l e s were l a i d down f o r t h e t r a n s m i s s i o n o f t h e b r e a k - u p and s p r i n g f l o o d a f t e r c o n s t r u c t i o n o f t h e dam. These p r i n ~ i p l e s ~ b r o a d l y s p e a k i n g , were a p p l i e d i n t h e s p r i n g o f 1940 and proved s u c c e s s f u l . The q u e s t i o n now a r i s e s t o what e x t e n t t h e e x p e r i e n c e s g a i n e d may be u t i l i z e d f o r f u r t h e r a p p l i c a t i o n , o r w h e t h e r t h e y may i n d i c a t e any change i n t h e method employed. T h i s s u b j e c t h a s b e e n d i s c u s s e d i n d e t a i l and t h e f o l l o w i n g r e p o r t i s s u b m i t t e d :

"The method employed i n t h e s p r i n g of 1940 was b a s e d p r i m a r i l y o n t h e a s s u m p t i o n t h a t t h e i c e c o v e r on t h e a r t i f i c i a l l a k e s h o u l d b e b r o k e n up o n l y a t t h e u p p e r e n d , b u t e l s e w h e r e s h o u l d be l e f t i n t a c t . The a l t e r n a t i v e

method would be t o b r e a k u p t h e i c e c o v e r o v e r a s much o f t h e l a k e a s p o s s i b l e , s t a r t i n g a t t h e w e i r a t Keggum. Combinations o f t h e two methods a r e a l s o p o s s i b l e .

k he u s e f L l l n e s s o f any method must b e judged f r o m v a r i o u s p o i n t s o f view, a s f o l l o w s :

1. P i l i n g u p a t F r i e d r i c h s t a d t ;

2 . S t r a i n on t h e w e i r s t r u c t u r e s , p a r t i c u l a r l y t h e w e i r d e f e n c e s ;

3 . Wear and t e a r on t h e t u m b l i n g b a y s , e t c . ;

4 . I c e c o n d i t i o n s between Keggum and Riga h a r b o u r ; 5 . O p e r a t i n g c o s t s and c o s t s o f i c e r e m o v a l * ' ~ V i t h a view t o p r e v e n t i n g a p i l i n g up a t F r i e d r i c h s t a d t i t would i n d e e d be a d v a n t a g e o u s t o ' b r e a k t h e i c e c o v e r o v e r t h e e n t i r e a r t i f i c i a l l a k e , b u t i n o u r o p i n i o n t h i s i s more t h a n i s n e e d e d . I t i s c l e a r , n e v e r t h e - l e s s , t h a t t h e i c e c o v e r must be e f f e c t i v e l y b r o k e n a t t h e u p p e r end o f t h e dam b a s i n ( C f . o u r Memorandum o f t h e 1 6 F e b r u a r y 1 3 3 9 ) ,

(20)

Page

-

15 Tech, T r a n s , TT-85 ''The r e m a i n i n g p o i n t s , 2 t o 5 , f a v o w t h e r e t e n t i o n of t h e i c e c o v e r , I n t h i s c o n n e c t i o n , however, p o i n t Z 0 r e q u i r e s f u r t h e r d i s c u s s i o n , I f t h e break-up e x e r t s i t s l a s t p r e s s u r e shock d u r i n g i t s g r a d u a l p r o g r e s s t h r o u g h t h e darn b a s i n ( a t Rembate) i t i s q u i t e p o s s i b l e t h a t t h i s shock might e x t e n d , under c e r t a i n c i r c u m s t a n c e s , a s f a r a s t h e w e i r d e f e n c e s o S i n c e t h l s i s u n d e s i r a b l e ,

i t a p p e a r s a d v i s a b l e t o f r e e t h e l a k e of i c e immediately ahead of t h e w e i r d e f e n c e s f o r a d i s t a n c e u p s t r e a m o f

s e v e r a l hundred m e t r e s , l1

I n t h e f o l l o w i n g s p r i n g , 1941,, t h e s i t u a t i o n became v e r y grave The huge masses of d e p t h i c e which had formed i n t h e r a p i d s of t h e Dvina d u r i n g t h e s e v e r e w i n t e r , and which had a l r e a d y c a u s e d i c e jams a t t h e upper end of Lake Keggun i n autumn, proved a s e r i o u s o b s t a c l e t o con- d u c t i n g t h e i c e i n t o t h e a r t i f i c i a l l a k e d u r i n g t h e b r e a k - up. The masses of i c e c o u l d n o t be accommodated, b u t had t o b e conducted v e r y l a b o r i o u s l y t h r o u g h t h e w e i r i n a s e r i e s of removal o p e r a t i o n s w i t h a r i s e i n t h e w a t e r l e v e l of e i g h t m e t r e s , This came c o n s i d e r a b l y , above a l l e m b a n h e n t s , and f l o o d e d many s e t t l e m e n t s and r o a d s i n t h e v i c i n i t y of t h e l a k e , S e v e r a l f o r e i g n e x p e r t s who saw t h e break-up on t h e Dvina i n t h e s p r i n g or' 1 9 4 1 were a s t o n i s h e d a t t h e u n u s u a l l y d i f f i c u l t i c e c o n d i t i o n s o The R u s s i a n e x p e r t s m a i n t a i n e d t h a t such a v a s t movement of i c e i n t h e e i g h t t o e i g h t e e n metre deep and f i v e hundred t o f i f t e e n hundred m e t r e wide dam b a s i n of t h e Keggum Power P l a n t had no p r e c e d e n t e i t h e r i n t h e e x p e r i e n c e of t h e R u s s i a n power developments or i n t h e l i t e r a t u r e ,

The g e n e r a l o u t l o o k i n t h e s p r i n g of 1941 was v e r y gloomyo The damage caused b y the w a t e r and i c e c o u l d b e e s t i m a t e d a t s e v e r a l m i l l i o n Reichsmarks, The w o r s t

f e a t u r e , however, was t h e f a c t t h a t no p r o s p e c t w a s s e e n f o r improving t h e s i t u a t i o n i n t h e f u t u r e , It seemed a s i f t h e o u t l a y f o r a l l t h e newly c o n s t r u c t e d embankments, r o a d s and b r i d g e s , i n F r i e d r i c h s t a d t a s w e l l a s i n many o t h e r s e t t l e - ments, would have t o be w r i t t e n o f f a s a t o t a l l o s s ,

I V INVESTIGATIOIJS OF TII3 DEPARTMZNT OF MARINE ON TIE: D V I N A I N

THE WINTGRS OF 1941-42 and 1942-43

The o b s e r v a t i o n s and e x p e r i e n c e s of p r e v i o u s y e a r s had a l r e a d y shown v e r y c l e a r l y t h a t t h e g r e a t e s t d i f f i -

(21)

Page 16

Tech. Trans. TT-85

in its swift-water section, were caused by the soft masses of depth ice. In designing and building the Keggum gower

Plant the Swedish firm Aktiebolagetvattenbyggnadsbyron had

indeed correctly estimated the quantity of ice in the Dvina, but had not given sufficient consideration to the properties o f the different kinds of ice, i.e., they had not appreciated the difficulties that may be caused by the depth ice. The course o f the break-up in the spring of

1941 showed that special investigations o f the ice con-

ditions, particularly in the swift-water section would have to be begun immediately in order to find ways and means of combatting the formation o f the unwanted depth ice, or at least of obtaining a more favourable grouping o f the soft depth ice masses so as to prevent the dangerous ice jams in the spring.

The author, after acquainting himself more closely with the research results o n ice conditions in the rivers of Russia, Norway and Sweden, worked out a program o f investigations and submitted it to the De'part- ment of Marine. This plan was studied in#consultation with the management o f the Keggum Power Plant and the experts at Higa University, and the work in question was begun in the fall o f 1941. The author was placed in

charge of the research.

The program comprised mainly the investigation

of the thermal and dynamic conditions of the formation

of depth ice, the observation o f the formation of the ice cover and the associated change of water level, the

measurement o f the ice quantities, the investigation of ground ice formation and observation of the course of the

break-up i n the, Dvina. For this purpose twenty auxiliary

observation posts were set up in the research region on the section o f the river between Jakobstadt and Riga, in addition to the thirteen posts already in existence. For clarification o f the hydrological and meteorological aspects of the problem three hydro-meteorological stations and six posts for the observation of depth ice were also erected in the same district.

The formation of the depth ice was to be limited by trying to get a covering o f surface ice over the rapids of the Dvina. To give a better understanding of the idea underlying the methods employed, the foraation of the ice and the ice cover i n the swift-water section will be

(22)

Page

-

1 7

Techn Trans. TT-85

( a ) Formation of t h e I c e : The Various Types of I c e and

t h e i r F r o p e r t i e s I n t h e autumn when t h e t e m p e r a t u r e of t h e w a t e r d r o p s t o t h e f r e e z i n g p o i n t a b o r d e r of i c e i s g e n e r a l l y s e e n a l o n g t h e banks of t h e r i v e r . Beginning a t s o l i d c r y s t a l l i z a t i o n c e n t r e s on t h e s h o r e o r on t h e s u r f a c e of t h e w a t e r i t s e l f , t h e i c e c r y s t a l s i n t h e s u p e r c o o l e d s u r f a c e l a y e r of t h e w a t e r grow i n t h e form of wide, b u t a t f i r s t v e r y t h i n , c r y s t a l l i n e b r a n c h e s ( F i g . 4 and 5 ) , u n t i l t h e e n t i r e s u r f a c e of t h e w a t e r i s c o v e r e d w i t h a t h i n , smooth l a y e r of i c e c a l l e d s u r f a c e i c e ( F i g o 6 ) "

T h i s i n c r e a s e s i n t h i c k n e s s due t o f r o s t a c t i o n . I n t h e s w i f t - w a t e r s e c t i o n of t h e Dvina t h e p r o c e s s of i c e f o r m a t i o n i s much more c o m p l i c a t e d , With t h e a d v e n t of t h e f p o s t o n l y a narrow i c e b o r d e r forms owing t o t h e s w i f t n e s s of t h e c u r r e n t ( F i g . 7 ) ; a t t h e same t i m e , however, i c e b e g i n s t o c r y s t a l l i z e throughout t h e e n t i r e f l o w of s u p e r c o o l e d w a t e r from t h e s u r f a c e t o

t h e bed. Various p e c u l i a r t y p e s of i c e a r e formed w i t h

p r o p e r t i e s e n t i r e l y d i f f e r e n t from t h o s e of t h e s u r f a c e i c e ,

The famous Norwegian p h y s i c i s t , Olav Devik, v e r y a p p r o p r i a t e l y c a l l s t h e p r o c e s s of s u r f a c e i c e f o r m a t i o n a s t a t i c one and t h a t of i c e f o r m a t i o n i n f a s t w a t e r s a

dynamic one. )

The complex dynamic p r o c e s s of i c e f o r m a t i o n h a s t h u s f a r r e c e i v e d l i t t l e a t t e n t i o n o S e v e r a l t h e o r i e s have been a dvanced. Opinions d i f f e r g r e a t l y , p a r t i c u l a r l y

w i t h r e g a r d t o t h e manner i n which t h e ground i c e o r i g i n a t e s , C o n s i d e r a b l e d i f f e r e n c e s a l s o p r e v a i l i n t h e l i t e r a t u r e on tlie s u b j e c t w i t h r e s p e c t t o ' t h e t e r m i n o l o g y f o r t h e v a r i o u s t y p e s of i c e , The r e s e a r c h e s c a r r i e d o u t by t h e Department of i n r e c e n t y e a r s show t h a t t h e dynamic p r o c e s s of i c e f o r m a t i o n o c c u r s unde.r t h e f o l l o w i n g c o n d i t i o n s : 1) when t h e i c e - f r e e s u r f a c e i s s u p e r c o o l e d ; 2 ) when c r y s t a l l i z a t i o n c e n t r e s ( e o g o b o d i e s f l o a t i n g b e n e a t h t h e s u r f a c e , g r a i n s of s a n d , snow c y r s t a l s , e t c , ) a r e p r e s e n t f r o m which c r y s t a l l i z a t i o n c a n b e g i n ;

6 ) ' Olav Devik: Thermische und d v n m i s c h e ~ e d i n ~ u n g e n d e r E i s b i l d u n g i n " Wasser- l a e & e n (Thermal and Dynamic C o n d i t i o n s of I c e f o r m a t i o n i n Water C o u r s e s ) ,

(23)

Page

-

18 Techo T r a n s . T T - 8 5 3 ) when t h e r e a r e e d d i e s ( o r w a v e s ) , which promote f a v o u r a b l e c r y s t a l l i z a t i o n c o n d i t i o n s i n t h e s u p e r c o o l e d w a t e r l a y e r s T h i s s t a t e m e n t i s c o n f i r m e d by t h e f o l l o w i n g e x p e r i m e n t s . If a s t i c k of wood i s p l a c e d i n t h e c u r r e n t d u r i n g c o l d we at he^ ( F i g - 8 ) i c i n g t a k e s p l a c e o n l y on one s i d e o f t h e wood, t h e downstream s i d e . I f two s t i c k s a r e p l a c e d i n t h e s t r e a m i n s u c h a way t h a t t h e eddy f r o m t h e f i r s t s t i c k e n v e l o p e s t h e s e c o n d , i c e w i l l b e g i n t o f o r m o n l y a b o u t t h e s e c o n d s t i c k ( F i g , 9 and

l o ) , ,

A

lump of i c e was produced a r t i f i c i a l l y u n d e r f a v o u r a b l e

we at he^ c o n d i t i o n s i n t w e n t y - f o u r h o u r s a t a p l a c e where t h e r i v e r was t h r e e m e t r e s d e e p o The lump c o u l d b e

s h i f t e d a b o u t f r e e l y a s d e s i r e d , a n d w i t h i n f o u r d a y s i t

h a d grown s o l a r g e t h a t a man was a b l e t o w a l k a b o u t on i t ( F i g . 11),

The above p r o c e d u r e showed t h a t i t w a s p o s s i b l e t o p r o d u c e a d e p t h i c e f o r m a t i o n anywhere on t h e r i v e r . T h i s was a c o n s i d e r a b l e a d v a n t a g e f o r f u t u r e work. The o b s e r v a t i o n s a l s o showed t h a t t h r o w i n g a r t i f i c i a l c r y s t a l l i z a t i o n c e n t r e s (snow o r s a n d ) i n t o t h e open c u r r e n t had t h e e f f e c t o f i n t e n s i f y i n g t h e d e p t h i c e f o r m a t i o n . The d e p t h i c e i s n o t a l w a y s of t h e same t y p e , b u t c a n v a r y v e r y c o n s i d e r a b l y w i t h t h e d e g r e e of s u p e r - c o o l i n g o f t h e w a t e r , t h e r a t e of c r y s t a l l i z a t i o n a n d o t h e r c o n d i t i o n s , On t h e b a s i s of t h e o b s e r v a t i o n s a n d e x p e r i e n c e s o f t h i s i n v e s t i g a t i o n t h e f o l l o w i n g c l a s s i f i c a t i o n of i c e t y p e s i s recommended: ( i ) by o r i g i n , a n d ( i i ) b y s t r u c t u r e a n d p r o p e r t i e s . ( i ) I n t h e c l a s s i f i c a t i o n by o r i g i n t h e t e r m " s u r f a e , I t ? i c e f 7 , R u s s i a n " l y o d poverkhnostnytT, E n g l i s h " c h i e f i c e is-recommended f o r i c e formed by t h e s t a t i c p r o c e s s , a n d t h e t e r m " d e p t h i c e " , c o r r e s p o n d i n g o t h e R u s s i a n "podvodny l y o d " a n d t h e E n g l i s h " c u r r e n t icerft! f o r t h a t which i s b r o u g h t i n t o e x i s t e n c e b y t h e dynamic p r o c e s s , t ) T r a n s l a t o r f s n o t e : No p r e c e d e n t c o u l d be f o u n d f o r t h e s e t e r m s i n E n g l i s h and t h e more l i t e r a l t r a n s l a t i o n s of t h e German t e r m s have t h e r e f o r e b e e n r e t a i n e d "

Figure

Table  of  Contents  ( c o n t f d )
Figure  2  The  embe  % p i d e   at  s$ock  n&of  (149  km.  from  mou%h),
Figure  7  The  Dvina  a%  Bliarberg  (3141 km.  from  rnrauth)s  border  ice only  in  a narrow  s t r i p   a l o n g   the  bsnk,  &if%  ice i~  t h e   een%re  sf t h e   river
Figure  13  G e l a t i n o u s   ice  and  ground  ice 4n  $he  Dvina,
+7

Références

Documents relatifs

This paradox can be implemented through a quantum circuit where a ‘‘living’’ qubit (i.e., a bit in the state 1), goes back in time and tries to ‘‘kill’’ itself, i.e., flip

Starting from a set of fitted models with increasing number of fascicles, we use Akaike information criterion to estimate the probability of each can- didate model to be the

It describes available technology and current unmet needs, and presents the solution of an open-standard based application platform for improving access to vehicle

I1 confront0 delle varie norme indica perb che vi i: un'ampia differenza fra i requisiti fisici e chimici (Tab. La qualiti delle materie prime disponibili per la produzione

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin

Both space charge generation and transport mechanisms within PTFE busbar solid insulators, show a significant impact of the nature, the quantity and the

Representation of the tumor microenvironment (TME) with tumor-associated macrophages (TAMs), mesenchymal stromal/stem cells (MSCs), regulatory T-cells (T-regs), and

Cependant, les outils de modélisation qui composent la chaîne de prévision ont cruellement besoin de prévisions multivariées, c’est-à-dire de prévisions qui concernent