Chapter 3 Collection of Hydrologic Data

25

Chapter 3

COLLECTION OF HYDROLOGIC DATA 3.1

STREAMFLOW Continuous streamflow records a r e obtained a t a gaging s t a t i o n a t which t h e

stream stage (water-surface o r is recorded continuously.

h e i g h t above some datum) i s e i t h e r r e a d f r e q u e n t l y D i s c h a r g e i s measured,

u s u a l l y by c u r r e n t m e t e r ,

a t v a r i o u s s t a g e s f o r d e f i n i n g t h e stage-discharge r e l a t i o n ( r a t i n g curve) which

i s used t o convert the stage record t o a discharge record.

Only t h e g e n e r a l

p r o c e d u r e s a r e g i v e n h e r e ; f o r more d e t a i l s e e WMO (1980) o r Rantz (1982). 3.1.1

S t a g e measurement

Gaging s t a t i o n s a r e o f s e v e r a l t y p e s .

The s i m p l e s t c o n s i s t s o f a s e r i e s of

s t a f f g a g e s (Fig. 3.1) on w h i c h an o b s e r v e r r e a d s t h e s t a g e o n e or more t i m e s a

Fig. 3.1. day.

S t a f f g a g e s on Rio C i a , B r a z i l .

Recording g a g e s e i t h e r s e n s e t h e w a t e r s u r f a c e i n a s t i l l i n g w e l l hydraul-

i c a l l y c o n n e c t e d t o t h e s t r e a m o r by means o f a gas-purge

( b u b b l e gage) s y s t e m

w h i c h m e a s u r e s t h e p r e s s u r e on an o r o f i c e p e r m a n e n t l y m o u n t e d i n t h e s t r e a m . R e c o r d i n g g a g i n g s t a t i o n s a l s o h a v e s t a f f g a g e s ( F i g . 3.2) f o r v e r i f y i n g t h e s t a g e s b e i n g s e n s e d b y t h e equipment.

A simplified stilling-well

installation

is shown i n F i g u r e 3.3 and a g a g i n g s t a t i o n s t r u c t u r e i n F i g u r e 3.4. A bubble-gage

i n s t a l l a t i o n c o n s i s t s of an i n s t r u m e n t s h e l t e r on a c o n c r e t e

s l a b on t h e r i v e r bank. A t u b e c o n n e c t s t h e i n s t r u m e n t t o t h e o r o f i c e i n t h e stream.

N i t r o g e n gas i s bubbled t h r o u g h t h e o r o f i c e t o a c t u a t e t h e s e n s o r .

26

Fig. 3.2.

Lor-rater staff gage.

Fig. 3.3.

Simplified stilling-well installation.

Recording instruments are either analog or digital.

The latter produces a

punched-tape record for processing by digital computer; the punch interval commonly used is 15 minutes but this can be as short as 5 minutes or an hour.

as

long as

The two types of recorders are shown in Figures 3.5 and 3.6.

A gaging station should be located above a stable section of channel in order

that the relation between stage and discharge be well defined and unchanging

21

Fig. 3.4.

Gaging station.

Fig. 3.5.

Analog water-stage recorder.

with time.

T h e feature of the channel that maintains a more-or-less

stage-discharge relation is called the control.

stable

The control m a y be at a sec-

tion, such as a stable riffle ( F i g . 3.7) o r it m a y be a fairly long reach of the

28

F i g . 3.6.

D i g i t a l water-stage

F i g . 3.7.

Natural section control.

channel i t s e l f .

recorder.

A r t i f i c i a l s e c t i o n c o n t r o l s s u c h a s l o w dams a r e s o m e t i m e s

c o n s t r u c t e d where n a t u r a l channel f e a t u r e s a r e n o t s u i t a b l e . t r o l s a r e expensive,

e s p e c i a l l y f o r l a r g e streams,

A r t i f i c i a l con-

and a r e hard t o m a i n t a i n i n

e r o d i b l e c h a n n e l s c a r r y i n g heavy s e d i m e n t loads. 3.1.2

D i s c h a r g e measurement

D i s c h a r g e m e a s u r e m e n t s o f s t r e a m s a r e u s u a l l y made by currant-meter.

The

p r o c e d u r e c o n s i s t s o f (1) m e a s u r i n g t h e w i d t h , d e p t h , a n d v e l o c i t y o f f l o w i n

29 e a c h of s e v e r a l s u b s e c t i o n s of a s t r e a m c r o s s s e c t i o n , ( 2 ) c o m p u t i n g t h e d i s c h a r g e i n e a c h s u b s e c t i o n a s t h e p r o d u c t of a r e a and mean v e l o c i t y , summing t h e p a r t i a l d i s c h a r g e s t o o b t a i n t h e t o t a l .

and (3)

R e f e r r i n g t o F i g u r e 3.8.

t h e d e p t h a t e a c h of t h e s e l e c t e d v e r t i c a l s i s m e a s u r e d by s o u n d i n g and t h e width of each s u b s e c t i o n i s computed from t h e spacing of t h e v e r t i c a l s .

A t each

v e r t i c a l t h e mean v e l o c i t y i s o b t a i n e d from one or more v e l o c i t y o b s e r v a t i o n s by

Verticals

Meter locations

F i g . 3.8. S t r e a m c r o s s s e c t i o n showing m e t e r l o c a t i o n s f o r a d i s c h a r g e measurement. c u r r e n t meter.

Many s t u d i e s have demonstrated t h a t t h e mean of t h e v e l o c i t i e s

a t 0.2 and 0s of t h e d e p t h f r o h t h e w a t e r s u r f a c e i s v i r t u a l l y t h e mean velocity i n the vertical. mean i n t h e v e r t i c a l .

L i k e w i s e t h e v e l o c i t y a t 0.6 d e p t h v e r y n e a r l y e q u a l s t h e V e l o c i t y o b s e r v a t i o n s a r e u s u a l l y made a t 0.2 and 03 of

t h e depth i n each v e r t i c a l where t h e depth i s adequate. The b a s i c equipment needed f o r a d i s c h a r g e measurement c o n s i s t s of a c u r r e n t meter,

a d e v i c e f o r i n d i c a t i n g t h e r e v o l u t i o n s of t h e meter,

a s t o p watch,

and

some means of measuring d e p t h and w i d t h and of holding t h e m e t e r i n t h e proper l o c a t i o n s for v e l o c i t y observations.

In shallow s t r e a m s , measurements a r e made

by wading; t h e c u r r e n t meter i s mounted on a wading rod which i s used t o measure d e p t h and t o p o s i t i o n t h e m e t e r i n t h e v e r t i c a l .

H o r i z o n t a l c o n t r o l i s main-

t a i n e d by a t a p e or b e a d e d w i r e s t r e t c h e d a c r o s s t h e s t r e a m .

See F i g u r e 3.9.

In use, t h e number of r e v o l u t i o n s of t h e meter r o t o r i s obtained by an e l e c t r i c a l c i r c u i t w h i c h p r o d u c e s c l i c k s i n a n e a r p h o n e or r e g i s t e r s o n a c o u n t i n g device.

Elapsed t i m e i s measured by a stopwatch.

v e l o c i t y through t h e meter r a t i n g t a b l e . measurement.

These d a t a a r e t r a n s l a t e d t o

F i g u r e 3.10 shoks n o t e s of a d i s c h a r g e

30

F i g . 3.9.

Wading equipment and a measurement i n p r o g r e s s .

Deep s t r e a m s a r e m e a s u r e d f r o m a b r i d g e , c a b l e w a y , o r b o a t .

The m e t e r i s

suspended on a c a b l e above a sounding weight which i s used f o r d e p t h measurement and t o h o l d t h e c u r r e n t m e t e r a t t h e c o r r e c t p o s i t i o n i n t h e v e r t i c a l f o r v e l o c i t y observation.

Sounding w e i g h t s used range from 1 5 t o 300 pounds or more

depending on t h e d e p t h and v e l o c i t y of t h e stream. i n F i g u r e s 3.11,

3.12,

and 3.13.

Methods of gaging a r e shown

S e e Buchanan a n d S o m e r s ( 1 9 6 9 ) f o r a m o r e

complete d e s c r i p t i o n of measurement t e c h n i q u e s i n c l u d i n g measurement under i c e cover. The m o v i n g - b o a t velocity-area

method i s s i m i l a r t o t h e above method i n t h a t i t u s e s t h e

approach t o d e t e r m i n i n g d i s c h a r g e b u t i t d i f f e r s i n t h e method of

d a t a c o l l e c t i o n ; t h e de?t:..

r n d v e l o c i t i e s a t e a c h o b s e r v a t i o n p o i n t a r e ob-

tained while the boat is rapidly traversing the cross section.

Thus a measure-

ment of d i s c h a r g e by t h i s method c a n be made on wide s t r e a m s i n a few m i n u t e s a t s i t e s without fixed f a c i l i t i e s .

However,

made and t h e r e s u l t s a v e r a g e d .

The e q u i p m e n t ( F i g . 3.14) c o n s i s t s o f a s o n i c

sounder,

a vane w i t h a n g l e i n d i c a t o r ,

in practice 6 traverses usually are

a component p r o p e l l o r - t y p e

c u r r e n t meter.

and a maneuverable s m a l l boat. The t r a v e r s e o f t h e c r o s s s e c t i o n i s made w i t h o u t s t o p p i n g a n d d a t a a r e collected a t regular intervals.

The b o a t o p e r a t o r m a i n t a i n s c o u r s e by "crab-

b i n g " i n t o t h e d i r e c t i o n of f l o w s u f f i c i e n t l y t o keep on l i n e .

The f o r c e

e x e r t e d on t h e c u r r e n t m e t e r i s t h e c o m b i n a t i o n of two f o r c e s a c t i n g s i m u l t a neously,

one f o r c e d u e t o t h e movement o f t h e b o a t a n d t h e o t h e r f r o m t h e

o t r e a m f l o r normal t o t h e path.

A d d i t i o n a l i n f o r m a t i o n needed i s t h e v e r t i c a l

........................................................... qz"uan ........................................................................ ..............................................

.......

-

. . . .

..."a?3....... I

0Al"q)

...............................................

-

..................................................................... r,rmqiJ py,"s )q,", ................ p'"nu,, p , ~ , ~ n..........................

..........

-

~

.qo i+,p.J"~u

........ . . .................. .... ...... P.3 o,... a , . & ........ ~,~... . . . *y ........................................... 'WJ .......................... -* ?nj.?.... , ~ y l , ~ & ..................... &.zc J., Iu .~ ..... ............................. . . . . . . . . . . . . . "Dll,al "0'3 : N O I I ! p Y O > ~~~

'i~~LUs

yuqpJ"0 p m q

-

'(0'8

n r o ) rmd

'(Oh@) I!*)

...... .... ... ............................................. ............. .................... ........................... pYmJ 9.93 ',.q-q>q,

,.

.......................................

PY.

. 1 . *

CI

'(0'5)

pms '(%Z)

>">[,a,.>

..

p3p,

....

l"?w,inrwly H 3

n 8-2

3 W Pilix"b

Ib!'B:./4!18.l?:!'s:l:::::::::+c:~! ,

H

32

Fig. 3.11.

Gaging from a bridge (during a flood at left).

F i g . 3.12.

Measuring from a cableway.

the stage-discharge relation w i l l change either gradually or abruptly in response to such factors as aquatic growth, ice formation and release, erosion or deposition by floods, and other natural or man-made changes in the channel.

The

definition and application of rating curves require an understanding of stream hydraulics and considerable experience. Kennedy (1983).

S e e WYO (1980) or R a n t z

(1982). and

33

F i g . 3.13.

J e t b o a t equipped f o r gaging.

I ,Indicator

Sighting d e v i c e \

I

-

L

/"

and dial

L

I

F i g . 3.14. E q u i p m e n t f o r m e a s u r i n g by t h e m o v i n g - b o a t m e t h o d (From Smoot and Novak, 1969).

A stage-discharge

r e l a t i o n c a n be computed from a s u r v e y of t h e downstream

channel and e s t i m a t e s of channel roughness. backwater method,

The technique,

known a s t h e s t e p -

i s u s e f u l where t i m e does n o t p e r m i t o b t a i n i n g c u r r e n t - m e t e r

d i s c h a r g e measurements throughout t h e range of s t a g e , or where h i g h accuracy i s not required.

The method i s d e s c r i b e d i n many h y d r a u l i c t e x t s and by Davidian

(1984) and was v e r i f i e d for t h i s a p p l i c a t i o n by B a i l e y and Bay (1966).

34

Fig. 3.15

Stage-discharge relation (rating curve).

Streamflow records are sometimes needed on stream reaches affected by variable backwater.

T h e discharge past a section on such a reach is a function of

stage and the slope of the water surface through the reach.

A continuous stage

record at each end o f a reach is required to define the slope. analysis depends on the hydraulic conditions.

The method of

See W M O (1980) or Bantz (1982).

and Kennedy (1983) for rating curve theory and details of applications to various channel and flow conditions. 3.1.4

Discharge computation and the hydrograph

Given a continuous stage record or frequent stage observations, and a stagedischarge relation, the discharge can be computed for any particular time within the period of stage record.

Daily mean discharges are usually computed although

discharges at intervals of an hour or less are used to define the changes during a flood.

An annual s t r e a m f l o w record as published b y U S G S is s h o w n in F i g u r e

3.16. The daily mean discharges of Figure 3.16 the hydrograph shown in Figure 3.17. various events.

are plotted against time to produce

Hydrographs show how a stream responds to

An uncharacteristic pattern of a segment of a hydrograph may

indicate s o m e unnatural f l o w modification o r an error in the record or in t h e analysis on which the discharge record is based. Flood hydrographs are usually defined by discharges at short intervals, such as hourly, and by the peak discharge. 3.1.5

Figure 3.18

is an example.

Special gaging methods

Variable backwater due to operation of a dam or other control on a stream may result, at times, in

SO

little fall in the r a t e r surface through a reach that

35

POTOMAC RIVER BASIN

183

01600000 NORTH BRANCH POTOMAC RIVER AT PINTO, MD Mineral County, W. Va., Hydrologic Unit 02070002, on right bank a r downLOCATION.--Lat 3 9 " 3 3 ' 5 9 " , long 78'50'25''. stream side of Western Maryland Railway bridge at Pinto, 2.8 m i ( 4 . 5 km) downstream from M i l l Run, and a t mile 3 2 . 6 (52.5 km). DRAINAGE AREA:-S96

mi'

(1.544

krn'). WATER-DISCHARGE RECORDS

PERIOD OF RECORD.~-October1 9 3 8 to current year REVISED RECORDS.--WSP 1332:

1943

GAGE.--Water~stagerecorder. Datum of gage is 648.23 ft (197.581 rn) National Geodetic YeTtxCal Datum of 1 9 1 9 . P r i o r to Dec. 10, 1938, "onrecording gage at highway bridge 2 5 0 ft (76 a) downstream at same datum. REMARKS.--Water-dischargerecords good except those for winter periods. uhxch are fair. Some regulation at low flow by Stony River Reservoir, 6 6 m i (106 km) above statxon ( s e e statxon Ol59S200), and since December 1950, by Savage River Reservoir, 25 "11 ( 4 0 ke) above Station ( s e e Station 0 1 5 9 7 5 0 0 ) . AVERAGE DISCHARGE.--41 years, 886 ft'ls

(25.09 m ' l s ) ,

20.19 inlyr (513 mnlyr), unadJusred.

EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 37,000 ft'ls (1,050 " ' I s ) Oct. 16, 1954. gage height, 23.23 ft (7.081 n); minimum, 31 ft'ls (0.88 m'ls) Dec. 18, 19, 1 9 4 3 , gage height, 1.37 fr (0.418 m), result of freereup. EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of Mar. 29. 1924, reached a stage of about 24 ft (7.3 m), discharge. Flood of Mar. 17 1936. reached a stage of about 23.5 ft (7.16 m). from about 5 5 , 0 0 0 ft3/s (1,560 m'/s). floodmarks, discharge, about 1 0 , 0 0 0 ft'lr ( 1 , 4 2 0 m i l s ) . EXTREMES FOR CURRENT YEAR.--Maximum discharge 1 2 800 ft'ls (362 r n ' l s ) Feb. 26. gage height, 13.28 ft ( 4 . 0 4 8 m ) ; minimum, 126 ft'ls (3.57 m'15) NO". 15. g a i e h;ight, 1.88 ft (0.573 m ) . D I S C H A R G E , I N CUSIC FEE7 PEH SECOND+ lb7ER 7 E b X OCTOBER I978 10 SEPTEUBER 1 9 7 9 UEbN VbLUES

011

OCT

NUV

OEC

JAN

FEB

MbH

1 2 3

171 172 111 165 113

111 170

695

603

6580

169 169

2410 3050

1750 3990 3870 2700

161 165 164

LO

114 171 169 168 172

164 163

2240 1500 15.0 3720 3050

11

171

1 63 164 167 165 152

179 184 183

250 618

1-3

1-1

I

5

6 7

8 9

16 17

169

1590

1180 1010

988 174 600 476 403

233 22* 206 270 260

115 406 911 $15 266

95.

1060

1140 1800 2890 22hO 1120 1630 1160 853

351 321 318

471

232 205 179

3180

908 835 790 155

1310 1180 1090

735 711 698 L I D ,a 1

739 897 1600

1000 1500 1100

8.09 280 1090 152

Fig. 3.16.

2550

151 159 181

3bO 350 370 390 450

2330

TOTAL l07AL

3550

147

1190

209 217 463 1090 678

1078 1919

152

1170

631 376 286 2b3 230

1990 2090 17.0 1260 918

3330 3050 2060 1760 2680

YR I7R VR

586

1560 1680 1500

255 231 224 226 213

CAL

I k70 1290 1130 981 893

2210

6350 5480

I73

MAX *IN

564

10400 7890

21

5501 171 242 161

SEP

217 188 112 161 157

36Y

2-9

TOT&L WEbN

bUG

319 250 2bl 298 1140

320 380

xrr

_--

JUL

1030 899 710 8* 1 169

1340 1230 2050 1990 1610

514

i.0

183

JUN

1250 1080 96. 1LhO 1540

318

566

554

165 169 235 242 20 1

UbY

888

2160 2010 2220 2650

!:

26 21 28 29 30 31

APT(

,200 6140 6330 9570

483

4BP

509

1930

352 343

.'tP

730

850 1900

2410

3360

2310 2100 2210

2180 5390 9280 11100 1550 5220

loso

1530 1310 1200 1010 832 969

52h7 1702 3120 514

51295 1655 3990 139

54139 1955 11100 320

2200 1610 959

1030

390628 414643

UEbN

MEAN

107% 1136

_-_ ___ ---

MAX

*AX

10700 11100

6610

2710 2350 2010 2150

1810

low

1430

1054 1044 931

'. Dz o1 e0

,TO L.-q

1010 Y36 819 1160 2720

663 660 895 753

1150 1580

15.

TO,

111

631

595

625 1210 3080

2200 2040 1830 1530 968 817

746 1530

---

3090 2160 1590 1570 1310 2100

99270 3202

39624 1321 26511 660

43416 1k01 3090 595

io4ao

871

M I N 131

*IN 1+7

1880

1490 14OP

CFSw 1.80 CFSM 1.91

49h 502

631

; ; ;

.*a

P'a:;

333

236 241 245 231 215

300 255 217 229 228

191 172 161 180 253

---

366 215 195 210 213 284

14661 489 1170 161

9828 311 1140 195

; ; :

217 191 180

I 64 157 19, 443

509 572 330

690

39b 311 292

167 663 688 135 124

604

369

>=D

336

368 LIT0 1250 973 839 196 129 752 800

280

---

8164 263 911 147

26953 898 3550 292

669

IN 24.38

I N 25.88

Published annual streamflow r e c o r d .

the f a l l cannot be measured c l o s e l y enough ( o r i s a f f e c t e d by wind) for use i n a stage-f a l l - d i s c h a r g e

relation.

Several a l t e r n a t i v e s a r e a v a i l a b l e .

36

Fig. 3.17.

I:

Hydrograph of daily discharges of Figure 3.16.

20,000

I

10,ooo

-

I

z

W'

U

40 [r

1 m -

cn n

lqIl 10050 50 21

Fig. 3.18. (i)

I

t

'I

23

"I

"

l

25

27

,

1

JUNE 1972

Flood hydrograph.

Deflection meter.

The simplest alternative is use of a deflection vane

set at a fixed position below the minimum stage and at a right angle to the current (Fig. 3.19).

The angular deflection of the vane is a function of the

velocity in the cross section, and the stream stage is related to the cross sectional area.

Deflection and stage are measured at the gage site and the

relation with discharge is based on current-meter measurements. The deflection vane is used in small channels having little change in stage. Both downstream and upstream flow can be measured so it is suitable for tidal

37

High tide7

Low tidei

River bottom-

F i g . 3.19

Deflection-meter vanes.

channels.

D i s c h a r g e s c o m p u t e d by t h i s m e t h o d a r e g e n e r a l l y of low a c c u r a c y ,

e s p e c i a l l y t h o s e n e a r zero. ( i i ) A c o u s t i c method.

V e l o c i t y a t some f i x e d l e v e l i n t h e s t r e a m i s ob-

t a i n e d by d e t e r m i n i n g t h e t r a v e l t i m e s of sound i m p u l s e s moving i n b o t h d i r e c t i o n s along a d i a g o n a l p a t h between t r a n s d u c e r s (sound g e n e r a t o r s o r r e c e i v e r s ) mounted n e a r e a c h bank. shown i n F i g u r e 3.20.

The l a y o u t of a n o p e r a t i n g s y s t e m on Columbia River i s The i n s t a l l a t i o n a n d o p e r a t i o n o f t h a t s y s t e m i s deC a l i b r a t i o n i s by c u r r e n t meter.

s c r i b e d b y S m i t h and o t h e r s (1971).

Laenen

and S m i t h ( 1 9 8 2 ) h a v e a s s e m b l e d p u b l i s h e d and u n p u b l i s h e d i n f o r m a t i o n on t h e o p e r a t i o n , a p p l i c a t i o n s , performance, and l i m i t a t i o n s of a c o u s t i c v e l o c i t y measurement s y s t e m s w i t h s p e c i f i c a p p l i c a t i o n s t o measurement of streamflow. ( i i i ) E l e c t r o m a g n e t i c method.

tromagnetic meter.

P o i n t v e l o c i t y can b e measured by a n elec-

Continuous r e c o r d s of v e l o c i t y a t one p o i n t i n a c r o s s

s e c t i o n and of t h e s t a g e can b e t r a n s f o r m e d i n t o a continuous d i s c h a r g e r e c o r d a f t e r c a l i b r a t i o n w i t h c u r r e n t - m e t e r measurements.

The r e l i a b i l i t y of t h e

computed d i s c h a r g e depends on how c l o s e l y t h e v e l o c i t y a t t h e one p o i n t repres e n t s mean v e l o c i t y through t h e range of d i s c h a r g e experienced a s w e l l as on t h e r e l i a b i l i t y of t h e p o i n t v e l o c i t i e s .

Such a n i n s t a l l a t i o n s h o u l d b e o f r e l a -

t i v e l y low c o s t b u t t h e e l e c t r o m a g n e t i c m e t e r i s a l w a y s s u b j e c t t o damage from

38

Fig. 3.20. 1971).

Layout o f an a c o u s t i c v e l o c i t y measuring system (Smith and o t h e r s ,

d e b r i s i f i t i s s u i t a b l y located.

Lack of s t a b i l i t y of t h e m e t e r c a l i b r a t i o n i s

a l s o a problem. Green and Herschy (1978) d e s c r i b e an e l e c t r o m a g n e t i c g a g i i g s t a t i o n based on t h e total-flow

e l e c t r o m a g n e t i c method.

T h i s a p p l i c a t i o n i s s t i l l under develop-

ment. (iv)

D i l u t i o n methods.

D i l u t i o n methods o f measuring s t r e a m d i s c h a r g e a r e

u s e f u l under flow c o n d i t i o n s t h a t e x i s t i n s h a l l o w , Current-meter

e x t r e m e l y rough channels.

measurements a r e g e n e r a l l y q u i c k e r and more r e l i a b l e a t a l l b u t

extremely unfavorable s i t e s . The f i e l d p r o c e d u r e i n v o l v e s i n j e c t i n g a t r a c e r of g i v e n c o n c e n t r a t i o n i n t o a s t r e a m and sampling t h e c o n c e n t r a t i o n downstream where t h e t r a c e r i s c o m p l e t e l y mixed w i t h t h e w a t e r .

The t r a c e r may b e i n j e c t e d a s a s l u g o r a t a c o n s t a n t

rate.

U s e f u l t r a c e r s i n c l u d e s a l t s , r a d i o a c t i v e m a t e r i a l s , and f l u o r e s c e n t

dyes.

The method r e q u i r e s s k i l l e d o p e r a t o r s , c o n s i d e r a b l e t i m e ,

and a c o n s t a n t

discharge. Stream d i s c h a r g e for c o n s t a n t - r a t e Q =

injection is

c1 - c2 c -cb

2 where q i s t h e t r a c e r i n j e c t i o n r a t e and cb,

c1

and C2 a r e c o n c e n t r a t i o n s of t h e

39 stream a t t h e i n j e c t i o n p o i n t , of t h e i n j e c t e d t r a c e r , and of t h e s t r e a m a t t h e downstream c r o s s s e c t i o n r e s p e c t i v e l y .

See White (1978) or K i l p a t r i c k and Cobb

(1984) f o r d e t a i l s . 3.1.6

I n d i r e c t measurements

I t i s o f t e n i m p o s s i b l e t o measure f l o o d d i s c h a r g e s a t p a r t i c u l a r t i m e s because o f l a c k of a c c e s s t o t h e s i t e , s h o r t a g e of manpower, o r i n a d e q u a t e advance n o t i c e of t h e flood.

Engineers have t h e r e f o r e d e v i s e d methods of computing peak

d i s c h a r g e a f t e r t h e passage of t h e f l o o d : t h e common ones a r e slope-area, tracted-opening,

flow-over-dam,

and flo w -th rongh- cul ver t .

con-

These methods a r e

b a s e d on h y d r a u l i c e q u a t i o n s t h a t r e l a t e t h e d i s c h a r g e t o t h e w a t e r - s u r f a c e p r o f i l e , t h e geometry of t h e channel, and t h e channel roughness.

These measure-

ments may be e x p e n s i v e and t h e y a r e l e s s a c c u r a t e t h a n c u r r e n t - m e t e r

measure-

ment s. The s l o p e - a r e a m e t h o d i s t h e m o s t w i d e l y u s e d .

An i d e a l s i t e i s a r e a c h o f

u n i f o r m c h a n n e l on w h i c h t h e f l o o d p e a k p r o f i l e i s d e f i n e d on b o t h b a n k s by high-water

marks.

Surveys o f t h e s e p r o f i l e s and o f channel c r o s s s e c t i o n s ,

and

e s t i m a t e s o f t h e r o u g h n e s s c o e f f i c i e n t i n t h e Manning e q u a t i o n a r e r e q u i r e d . F i e l d e x p e r i e n c e i n s e l e c t i n g roughness c o e f f i c i e n t s i s d e s i r a b l e b u t guidance can be o b t a i n e d from t h e photographs i n t h e r e p o r t by Barnes (1967). I n d i r e c t methods a r e d e s c r i b e d by Barnes and Davidian (1978).

Users g u i d e s

t o t h e v a r i o u s t e c h n i q u e s a r e g i v e n by D a l r y m p l e and Benson (1967). B o d h a i n e (1968).

M a t t h a i (1968).

and Hulsing (1968).

Common t o a l l t h e s e methods i s t h e need t o s e l e c t t h e roughness c o e f f i c i e n t subjectively.

The roughness c o e f f i c i e n t o f a n a t u r a l channel i s a f u n c t i o n of

bed roughness,

bank i r r e g u l a r i t y ,

e f f e c t of v e g e t a t i o n ( i f any), d e p t h o f w a t e r ,

c h a n n e l s l o p e , and o t h e r f a c t o r s .

No o b j e c t i v e way o f c o m b i n i n g a l l t h e s e

e f f e c t s i n t o one c o e f f i c i e n t i s a v a i l a b l e .

F u r t h e r m o r e t h e v e r i f i e d v a l u e of a

roughness c o e f f i c i e n t f o r a p a r t i c u l a r channel r e a c h and f l o o d i s a f f e c t e d by i n a c c u r a c i e s i n measuring o t h e r v a r i a b l e s i n t h e Manning e q u a t i o n ; t h i s r e s u l t s i n some a p p a r e n t i n c o n s i s t e n c i e s among v e r i f i e d r o u g h n e s s c o e f f i c i e n t s . avoid t h i s s u b j e c t i v i t y .

Riggs (1976) developed a s i m p l i f i e d s l o p e - a r e a

To

method

i n w h i c h d i s c h a r g e i s r e l a t e d t o c r o s s - s e c t i o n a l a r e a and t o w a t e r - s u r f a c e slope.

A roughness c o e f f i c i e n t i s n o t used because, i n n a t u r a l channels, roughThe e q u a t i o n i s

n e s s and s l o p e a r e r e l a t e d . l o g Q = 0.366

+

1.33 log A

+

0.05 l o g S

-

0.056 ( l o g S ) *

w h e r e Q i s i n c f s , A i s a v e r a g e c r o s s s e c t i o n a l a r e a i n s q u a r e f e e t , and S i s d i m e n s i o n l e s s s l o p e of t h e w a t e r s u r f a c e through t h e reach. Mud f l o w s or d e b r i s f l o w s i n s m a l l ,

steep-gradient

channels leave physical

e v i d e n c e t h a t may b e m i s i n t e r p r e t e d a s i n d i c a t i n g t h e p a s s a g e o f a f l o o d .

A

40

flood-peak d i s c h a r g e computed fro m s u ch e v i d e n c e m i g h t b e e x t r e m e l y l a r g e , p o s s i b l y g r e a t e r t h a n t h e p o t e n t i a l f o r t h e b a s i n o r region.

Costa and J a r r e t t

(1981) d e s c r i b e how t o make t h e p r o p e r i n t e r p r e t a t i o n of t h e evidence. 3.1.7

Crest-stage

gaging s t a t i o n s

A c r e s t - s t a g e gaging s t a t i o n p r o v i d e s a r e c o r d of peak s t a g e s and t h e c o r r e s I t s purpose i s t o p r o v i d e d a t a f o r d e f i n i n g t h e

ponding d i s c h a r g e s a t a s i t e . flood-peak

f r e q u e n c y c h a r a c t e r i s t i c s where t h e c o s t o f c o l l e c t i n g a c o n t i n u o u s

s t r e a m f l o w r e c o r d cannot b e j u s t i f i e d .

A crest-stage

gage u s u a l l y c o n s i s t s of a 2-inch

t h e s t r e a m bank.

p i p e mounted v e r t i c a l l y on

The p i p e i s c a p p e d a t b o t h e n d s and c o n t a i n s a wooden s t a f f .

and i n t h e bottom cap, some ground cork.

I n t a k e h o l e s i n t h e bottom cap, and an

a i r h o l e i n t h e top cap, p e r m i t w a t e r t o e n t e r t h e p i p e a s t h e s t r e a m r i s e s . The c o r k f l o a t s on t h e w a t e r and some o f i t s t i c k s t o t h e s t a f f a t t h e c r e s t stage.

The gage i s i n s p e c t e d p e r i o d i c a l l y t o r e c o r d t h e c r e s t s t a g e ,

the staff,

t o clean

and t o r e p l e n i s h t h e cork.

Crest-stage

gages a r e u s u a l l y l o c a t e d where a s t a g e - d i s c h a r g e

computed from channel c h a r a c t e r i s t i c s , a r e a c h s u i t a b l e f o r step-backwater

r e l a t i o n can be

u s u a l l y above a b r i d g e o r c u l v e r t ,

analysis.

F i g u r e 3.21

o r on

shows a c r e s t - s t a g e

gage i n s t a l l a t i o n on a n ephemeral s t r e a m i n South Dakota. Data produced by c r e s t - s t a g e

gaging s t a t i o n s u s u a l l y a r e l i m i t e d t o t h e

maximum s t a g e and d i s c h a r g e e a c h y e a r , a l t h o u g h a d d i t i o n a l p e a k s may b e r e corded. 3.1.8

Time of t r a v e l

Time of t r a v e l i s u s u a l l y c o n s i d e r e d t h e mean t r a v e l t i m e of w a t e r p a r t i c l e s f l o w i n g from one c r o s s s e c t i o n t o a n o t h e r , a t a g i v e n d i s c h a r g e .

I t i s much

l o n g e r t h a n t h e t i m e r e q u i r e d f o r a f l o o d wave t o p a s s t h r o u g h t h e same reach. E s t i m a t e s o f t h e r a t e o f movement o f w a t e r b o r n e p a r t i c l e s i n s t r e a m s a r e needed f o r d e f i n i n g t h e w a s t e - a s s i m i l a t i v e

c a p a c i t i e s of s t r e a m s and t o f o r e c a s t

t h e movement of a s l u g of contaminant such a s might r e s u l t from a n a c c i d e n t a l spill. Various h y d r o l o g i c t r a c e r s such a s s a l t , have been used.

radioisotopes,

and f l u o r e s c e n t d y e s

The d y e Rhodamine WT i s a p o p u l a r t r a c e r .

It is injected

i n s t a n t a n e o u s l y a t a s t r e a m c r o s s s e c t i o n and t h e dye c o n c e n t r a t i o n is m o n i t o r e d a s t h e dye c l o u d p a s s e s each of a s e r i e s of c r o s s s e c t i o n s .

Dye c o n c e n t r a t i o n

i s measured by a f l u o r o m e t e r which i s s e n s i t i v e t o c o n c e n t r a t i o n s a s low a s 0.05 p a r t s per billion.

F i g u r e 3.22

shows t h e measured c o n c e n t r a t i o n a t f o u r p o i p t s

on t h e M i s s i s s i p p i R i v e r r e s u l t i n g f r o m t h e i n j e c t i o n o f d y e a t B a t o n Rouge. The maximum c o n c e n t r a t i o n d e c r e a s e s and t h e l o n g i t u d i n a l d i s p e r s i o n i n c r e a s e s w i t h d i s t a n c e downstream. l e a d i n g edge,

Time o f t r a v e l c a n b e e x p r e s s e d a s t i m e f o r t h e

t h e peak c o n c e n t r a t i o n , o r t h e l a s t d e t e c t a b l e dye t o p a s s a g i v e n

41

Fig. 3.21.

Crest-stage gage installation.

r B A T O N ROUGE

k

Q: 6700 M3/5EC.

I00 KM 147

20

KM

40 60 80 HOURS AFTER DYE RELEASE

202 KM (NEW ORLfANS)

100

I

Fig. 3.22. Distribution of dye concentration with time at midstream sampling points, Mississippi River, Louisiana, September, 1965 (From Wilson, 1968).

42 point.

A l l t h r e e t i m e s may b e n e e d e d f o r some p r o b l e m s .

D e t a i l s of time-of-

t r a v e l m e a s u r e m e n t s a r e g i v e n b y Hubbard a n d o t h e r s (1982).

See a l s o White

(1978) on d i l u t i o n gauging. t r a v e l i s g r e a t l y increased a s stream discharge i s decreased.

Time o f

Buchanan (1964) showed t h a t t r i p l i n g t h e d i s c h a r g e of Swatara Creek, Pa. reduced t h e t r a v e l t i m e about h a l f . r e a c h of S t .

Mary's

River,

T a b l e 3.1 s h o w s t r a v e l t i m e s t h r o u g h a 14.4 m i Indiana f o r a range i n discharge,

a s given by

Eikenberry and Davis (1976). TABLE 3 . l T r a v e l time v e r s u s d i s c h a r g e Discharge

T r a v e l time ( h o u r s )

cfs

% mean

22 120 620 810 1220

4.6 25 130 170 255

3.1.9

l e a d i n g edge

peak 1 30 40 .O 16.8 14.8 12 .o

105 33 .o 13.8 12.0 10.8

Sediment t r a n s p o r t

Sediment-laden

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

b u t i t a l s o d e p o s i t s s e d i m e n t i n c h a n n e l s , c a n a l s , and r e s e r v o i r s .

Thus, de-

s i g n e r s and o p e r a t o r s of w a t e r p r o j e c t s need i n f o r m a t i o n on t h e amounts and t i m e d i s t r i b u t i o n of sediment t r a n s p o r t e d so a s t o minimize t h e d e t r i m e n t a l e f f e c t s . Sediment i s t r a n s p o r t e d by a s t r e a m a s suspended sediment, which i s c o n t i n u a l l y i n suspension, and a s bed l o a d which moves by r o l l i n g , ing along t h e bottom.

sliding,

or bound-

The a m o u n t o f s e d i m e n t b e i n g t r a n s p o r t e d i s h i g h e s t

d u r i n g a p e r i o d of f l o o d r u n o f f because of t h e e r o s i o n produced by t h e c a u s a t i v e r a i n f a l l and because of t h e h i g h e r v e l o c i t i e s and t u r b u l e n c e i n t h e channels.

A sediment-discharge

measurement,

and a c o n c u r r e n t w a t e r - d i s c h a r g e

ment, p r o d u c e d a t a from w h i ch t h e f o l l o w i n g c a n be o b t a i n e d :

measure-

mean s u s p e n d e d

s e d i m e n t c o n c e n t r a t i o n , p a r t i c l e s i z e d i s t r i b u t i o n , s p e c i f i c g r a v i t y of t h e suspended sediment, t e m p e r a t u r e of t h e sediment-water m i x t u r e , w a t e r d i s c h a r g e , and t h e d i s t r i b u t i o n of flow i n t h e s t r e a m c r o s s s e c t i o n .

In a sediment-discharge

measurement water-sediment

selected v e r t i c a l s i n the cross section.

samples a r e c o l l e c t e d a t

The s a m p l e a t e a c h v e r t i c a l i s ob-

t a i n e d a s t h e s a m p l e r (Fig. 3.23) i s lowered t o t h e streambed and r a i s e d t o t h e s u r f a c e a t a uniform r a t e or, a l t e r n a t i v e l y , by c o l l e c t i n g samples a t s e l e c t e d points in the vertical. water-discharge

Laboratory analyses of t h e samples a r e used w i t h t h e

measurement t o p r o d u c e t h e d e s i r e d i n f o r m a t i o n .

g i v e n by Vanoni (1975, p. 317-349)

On s m a l l ,

Details are

and by Guy and Norman (1976)

f l a s h y streams n e a r l y a l l t h e sediment i s transported during t h e

s h o r t p e r i o d s of h i g h d i s c h a r g e .

Because t h e s e f l o o d p e r i o d s a r e r a r e l y known

43

F i g . 3.23.

Sediment sampler.

i n advance, a u t o m a t i c sampling equipment h a s been developed.

T h i s may b e a

s e r i e s of c o n t a i n e r s a t d i f f e r e n t e l e v a t i o n s f o r c a t c h i n g samples a s t h e s t r e a m r i s e s , or a pumping s a m p l e r p r o g r a m m e d t o t a k e s a m p l e s a t s e l e c t e d i n t e r v a l s according t o stream stage. Records o f sediment d i s c h a r g e o v e r a c o n s i d e r a b l e p e r i o d o f t i m e a r e needed t o d e f i n e i t s v a r i a t i o n w i t h s t r e a m f l o w and w i t h seasons, and t o d e f i n e t h e mean annual l o a d of sediment t r a n s p o r t e d .

If a d a i l y r e c o r d i s d e s i r e d , one or more d e p t h - i n t e g r a t e d

samples a r e t a k e n

e a c h d a y a t one v e r t i c a l : t n e s e a r e s u p p l e m e n t e d by p e r i o d i c , m o r e - d e t a i l e d suspended-sediment

measurements.

The d a i l y measured c o n c e n t r a t i o n s a r e p l o t t e d

on a c h a r t of gage h e i g h t a g a i n s t t i m e ( u s u a l l y t h e one from t h e analog r e c o r d e r a t t h e stream-gaging

s t a t i o n ) and t h e graph of s e d i m e n t c o n c e n t r a t i o n i s drawn

between observed p o i n t s u s i n g t h e s t a g e graph a s a guide. t i o n graph and t h e s t r e a m f l o w record, ( P o r t e r f i e l d , 1972).

From t h e concentra-

t h e d a i l y sediment l o a d can be computed

P a r t o f a p u b l i s h e d s e d i m e n t r e c o r d i s shown i n F i g u r e

3.24. The t o t a l suspended sediment l o a d f o r a y e a r c a n be approximated from occas i o n a l s e d i m e n t measurements by u s e of a s e d i m e n t - t r a n s p o r t d u r a t i o n curve.

curve and a flow-

The f o r m e r i s a p l o t o f s e d i m e n t d i s c h a r g e a g a i n s t s t r e a m

d i s c h a r g e ( F i g . 3.25) and t h e l a t t e r s h o w s t h e d i s t r i b u t i o n o f d a i l y s t r e a m d i s c h a r g e s during t h e y e a r (Chapter 5 ) .

The d u r a t i o n c u r v e i s d i v i d e d i n t o

i n t e r v a l s of t i m e and t h e mean d i s c h a r g e f o r e a c h i n t e r v a l i s determined.

This

d i s c h a r g e i s used t o d e f i n e t h e sediment t r a n s p o r t f o r t h a t i n t e r v a l of time. The a n n u a l s e d i m e n t d i s c h a r g e i s t h e sum f o r a l l o f t h e i n t e r v a l s . (1963) and,

f o r a n example,

See C o l b y

Simmons (1976).

The m e a s u r e m e n t s and t h e c o m p u t e d s e d i m e n t l o a d s d e s c r i b e d a b o v e a r e o f suspended sediment.

T o t a l sediment l o a d i n c l u d e s t h e bed l o a d which i s u s u a l l y

44

11477000 SUSPENDED-SEDIMENT

EEL RIVER AT SCOTIA, CA--Continued

OlSCtlAHGE ITONS/OAY), WATER YEAR 0CTlJt)ER 1979 TO SCPTEM~CF? 1980

OCTOBER

DAY

I

L

3

4

5 b

7

8

9

10

11

12 1>

ICFSL

106

1

I

.25 .50

.50 .5L -76 .78 .7e

98 96 99

3 3 3 3 3

21 22 23 24 25

2400 2540 2e20

2

3 3 3

I21

1

2 2 5

20

85 68 125 234 1740

472U

23000 20600 6580 3700 2540 1930

1150 220 10

35 16

1610

16

---

75726

TOTAL

-26

2 2

133 156 169 348 984

30 31

.29 .27

93 94 94 V6 96

16 17 18 19

ZY

SEDIMENT DISCHARGE ITDNSIDAY)

I 1

100 96 91 93

123

26 27 28

COiCENTRATlDN IYGILJ

DISCHARGE

1* 15

20

NOVEMBER

ME.M

MEAN

Fig. 3.24. computed,

.18 .18

.no

1.0 .9e -36 .e4 .91 4.7 53 624

b66

952 3630 122000 64000

3910 699 240 83 70

196743.1

MEAN DISCHARGE ICFSJ

MEAN CONCEN-

TRATION

1370 1340 SO50 11200 9270 14000

29000 15700 8960 6130

IMGILl

e

5220

20300

I2

33509 10400U 116U

3150 2900 2600 2500 2310

4s 24 16

563 237 131

2150 2020 1910

271

6890 lO8OOU 2140U 5230 2050

1 b50

1580 1540 1920 2860

95Y 5370 67800 28000

4540 8290 7980 30300 37600

220

6ezou

25700 15900 11300

355 215 105

lllU

9660 38300

218

536503

254350

14400

339u

7s 6L

11 LO

1160

55

359090

52 55 30 22 17

646 1260 340 I40 10

6460

--_

6180 5290 4550 3940 3440

12100 6010

12100 e440

26800 19000 12800 9510 7+m0

33

6510

tCF5l

MEAN CONCENIRATION IMGILL

MEAN DISCHARGE

400 240

390 160 90

7340 z&eoo 19500 25500

SCDIMLNT

DISCHAHGE ITONS/UAV)

30

9 196

4630 3660 3040 2610 22eo 34700

DtCEMBER

174

910 502 560

m600

643

151ou

295 150 94 55

518U

_--

24IU

--_-_

10 14

e

234

158 102 7s

101

e

46

e 5

4 5 4

10

38 I27 320 916 741

60

8680

e6e

786 369

54 62

6

1730

ITON51DAY)

10

b

ieoo

StO 1MEN1 DISCHARGE

1310

---

33 31 39 23

in

21 I7 52 293

inso

7160 4740 14500

iseoo

24600 9230 3100

1410 7070

144000

366945

Published sediment record. o r i s e s t i m a t e d a s a p e r c e n t a g e of t h e suspended load.

of bed load g e n e r a l l y a r e n o t r e l i a b l e .

Measurements

See Vanoni (1975).

I f a stseam f l o w s through a r e s e r v o i r most of t h e sediment w i l l b e t r a p p e d i n the reservoir.

The volume of m a t e r i a l d e p o s i t e d and i t s volume-weight

d e t e r m i n e d b y s u r v e y s a t i n t e r v a l s of s e v e r a l y e a r s.

can be

Of c o u r s e t h e r e s e r v o i r

outflow w i l l c o n t a i n some suspended m a t e r i a l ; t h u s t h e t o t a l i n f l o w load w i l l b e somewhat g r e a t e r than t h a t measured i n t h e r e s e r v o i r .

F i e l d measurement tech-

n i q u e s t o d e t e r m i n e t h e volume occupied by s e d i m e n t s d e p o s i t e d i n a r e s e r v o i r a r e d e s c r i b e d i n Vanoni (1975, p. 349-382).

Runoff and sediment y i e l d of ephe-

m e r a l s t r e a m s c a n b e o b t a i n e d f r o m d a t a c o l l e c t e d a t s m a l l r e s e r v o i r s a s des c r i b e d by P e t e r s o n (1962). 3.1.10

Chemical and b i o l o g i c a l q u a l i t y

Whether w a t e r i s c o n s i d e r e d of good or poor q u a l i t y depends on t h e use t o be made of it.

Drinking w a t e r should n o t c o n t a i n b a c t e r i a .

c e r t a i n m i n e r a l s , or d i s s o l v e d gases.

suspended m a t e r i a l s ,

Water f o r i r r i g a t i o n should c o n t a i n o n l y

45

100,000

I

I

I

40,000

10,000

4000

300 L 5000

I

10,000

I

I

20,000

50,000 100,000

DAILY MEAN WATER DISCHARGE, IN CFS

F i g . 3.25. Sediment-transport c u r v e f o r Sacramento R i v e r a t Sacramento. C a l i f o r n i a (From P o r t e r f i e l d , 1980). a l i m i t e d amount o f sodium and o f some o t h e r elements; and suspended sediment i s u n d e s i r a b l e because i t c l o g s t h e p i p e s and d i t c h e s . r e q u i r e w a t e r s o f v e r y s p e c i f i c c h e m i c a l content.

Some i n d u s t r i a l p r o c e s s e s Esthetically,

w a t e r i s con-

s i d e r e d good i f i t i s c l e a r ( h a s l i t t l e or no suspended or f l o a t i n g m a t e r i a l ) , h a s no c o l o r or odor, and s u p p o r t s f i s h and o t h e r b i o t a . Water q u a l i t y c a n be d e s c r i b e d i n two ways,

by i d e n t i f y i n g and q u a n t i f y i n g

the i n o r g a n i c and t h e o r g a n i c m a t e r i a l s i n t h e w a t e r , or by some measures o f t h e e f f e c t s of t h e s e m a t e r i a l s .

F o r example.

t h e c o n c e n t r a t i o n of d i s s o l v e d s o l i d s

is r e l a t e d t o t h e e l e c t r i c a l conductance: t h e t y p e s o f d i s s o l v e d s o l i d s d e t e r mine t h e pH,

a measure of hydrogen-ion

a c t i v i t y ; and t h e c o n c e n t r a t i o n of d i s -

s o l v e d oxygen is an i n d i c a t i o n of t h e b i o c h e m i c a l c o n d i t i o n of t h e water.

These

t h r e e i n d i c a t o r s p l u s t e m p e r a t u r e c a n b e m e a s u r e d i n t h e f i e l d a n d a r e good g e n e r a l measures o f w a t e r q u a l i t y .

But f o r c e r t a i n u s e s one needs t o know t h e

k i n d s a n d c o n c e n t r a t i o n s of t h e v a r i o u s d i s s o l v e d e l e m e n t s in t h e r a t e r . and

46

whether dangerous b a c t e r i a l or c h e m i c a l p o l l u t a n t s a r e p r e s e n t .

This informa-

t i o n i s o b t a i n e d by l a b o r a t o r y a n a l y s e s of samples o f w a t e r from t h e stream. D e t e r m i n a t i o n of w a t e r q u a l i t y i s a d e t a i l e d and s p e c i a l i z e d o p e r a t i o n a s i n d i c a t e d by t h e wide range of p h y s i c a l , chemical, b i o l o g i c a l , and r a d i o c h e m i c a l i n f o r m a t i o n p u b l i s h e d i n t h e a n n u a l w a t e r - d a t a r e p o r t s of t h e USGS f o r t h e

A purpose of t h e s e

N a t i o n a l S t r e a m - Q u a l i t y A c c o u n t i n g (NASQUAN) s t a t i o n s . NASQUAN s t a t i o n s i s t o m o n i t o r changes i n w a t e r q u a l i t y ,

consequently s p e c i f i c

conductance,

concentration a r e re-

pH.

water temperature,

corded continuously.

and dissolved-oxygen

T h i s d e t a i l i s n o t n e c e s s a r y on n a t u r a l ( u n p o l l u t e d )

w a t e r s whose c h a r a c t e r d o e s n o t c h a n g e a p p r e c i a b l y f r o m y e a r t o y e a r .

Hem

(1972. p. 40-50) d e s c r i b e s how e n v i r o n m e n t a l i n f l u e n c e s a f f e c t n a t u r a l w a t e r qua1 i ty. Methods f o r c o l l e c t i n g and a n a l y z i n g w a t e r - q u a l i t y o f t h i s book.

d a t a a r e beyond t h e scope

S e e Hem ( 1 9 7 2 , p. 60-68) f o r g u i d e l i n e s o f s a m p l i n g ; S k o u g s t a d

(1979) f o r d e t e r m i n a t i o n of i n o r g a n i c s u b s t a n c e s : B a r n e t t and M a l l o r y (1971) f o r d e t e r m i n a t i o n o f m i n o r e l e m e n t s ; G o e r l i t z and Brown ( 1 9 7 2 ) f o r m e t h o d s f o r a n a l y s i s o f o r g a n i c s u b s t a n c e s ; Greeson and o t h e r s (1977) for methods f o r coll e c t i o n and a n a l y s i s of a q u a t i c b i o l o g i c a l Thatcher, J a n z e r .

and m i c r o b i o l o g i c a l s a m p l e s ;

and Edwards (1977) f o r methods f o r d e t e r m i n a t i o n of r a d i o a c -

t i v e s u b s t a n c e s i n w a t e r ; and Stevens,

Picke,

and Smoot (1975) f o r measurement

of water temperature.

WEATHER OBSERVATIONS

3.2

The p r i n c i p a l w e a t h e r o b s e r v a t i o n s o f concern t o h y d r o l o g i s t s a r e p r e c i p i t a t i o n , t e m p e r a t u r e . and e v a p o r a t i o n from w a t e r s u r f a c e s . 3.2.1

.

Precipitation

A t most m e t e o r o l o g i c a l s t a t i o n s , t h e p r e c i p i t a t i o n i s caught i n a can and t h e c a t c h measured d a i l y .

The N a t i o n a l Weather S e r v i c e 8-inch nonrecording gage i s

shown i n F i g u r e 3.26.

D e t a i l s o f t h e gage and i n s t r u c t i o n s f o r making observa-

t i o n s a r e g i v e n by t h e N a t i o n a l Weather S e r v i c e (NWS, 1972). t a t i o n i s snow, t h e gage c a t c h may n o t be r e p r e s e n t a t i v e .

When t h e p r e c i p i -

Then a sample of snow

o n t h e g r o u n d i s o b t a i n e d b y i n v e r t i n g t h e c a n and c u t t i n g a v e r t i c a l s a m p l e which i s m e l t e d t o d e t e r m i n e t h e w a t e r c o n t e n t . Recording p r e c i p i t a t i o n gages commonly weigh t h e c a t c h and r e c o r d t h e cumulat i v e c a t c h on a n a n a l o g c h a r t or a s p u n c h e s a t s e l e c t e d i n t e r v a l s on a p a p e r tape. Data from t h e s e gages a r e commonly t a b u l a t e d a t h o u r l y i n t e r v a l s ; c a t c h e s a t s h o r t e r i n t e r v a l s c a n be o b t a i n e d most r e a d i l y from t h e d i g i t a l t a p e , l i m i t e d of c o u r s e by t h e punch i n t e r v a l . The t i p p i n g - b u c k e t r a i n g a g e , commonly u s e d i n h y d r o l o g i c s t u d i e s , i s a c t u a t e d by s m a l l i n c r e m e n t s o f r a i n ( u s u a l l y 0.01 i n c h e s i n U.S.). ments a r e r e c o r d e d on an analog c h a r t .

The i n c r e -

41

F i g . 3.26.

N a t i o n a l Weather S e r v i c e n o n r e c o r d i n g r a i n gage.

I n remote areas, p r e c i p i t a t i o n i s caught i n s t o r a g e gages, 8-inch cans of c o n s i d e r a b l e depth.

The c a n s a r e charged w i t h c a l c i u m c h l o r i d e t o m e l t snow and

t o prevent severe freezing of the catch. e v a p o r a t i o n between o b s e r v a t i o n s .

O i l i s sometimes used t o reduce

The c a n i s u s u a l l y e l e v a t e d on a tower and

e q u i p p e d w i t h a s h i e l d to r e d u c e w i n d v e l o c i t y ( F i g . 3 . 2 7 ) . serviced a t i r r e g u l a r intervals,

Storage gages a r e

sometimes o n l y 3 o r 4 t i m e s a year.

Generally

o n l y s e a s o n a l o r annual p r e c i p i t a t i o n i s o b t a i n e d . The c a t c h o f a p r e c i p i t a t i o n g a g e d e p e n d s on i t s l o c a t i o n w i t h r e s p e c t t o trees, buildings,

and o t h e r o b s t r u c t i o n s .

A l o c a t i o n i s considered s a t i s f a c t o r y

i f t h e r e a r e no o b s t r u c t i o n s w i t h i n a n i n v e r t e d 45-degree However,

cone above t h e gage.

a gage l o c a t i o n may become u n s u i t a b l e because of t r e e growth o r b u i l d -

ing construction.

Gages on windy,

open a r e a s tend t o c a t c h t o o l i t t l e p r e c i p i -

tation. A l t h o u g h a p r e c i p i t a t i o n g a g e may c o l l e c t s a m p l e s r e p r e s e n t a t i v e o f t h e immediate l o c a l i t y ,

t h e r e c o r d a t t h e s i t e may n o t d e s c r i b e t h e p r e c i p i t a t i o n

p a t t e r n some d i s t a n c e away, e s p e c i a l l y i n mountainous country. N a t u r a l p r e c i p i t a t i o n may be a f f e c t e d by man's a c t i v i t i e s .

Smoke and o t h e r

a i r b o r n e e f f l u e n t s from i n d u s t r i a l a r e a s t e n d t o i n c r e a s e p r e c i p i t a t i o n downwind, and l a r g e urban a r e a s become h o t t e r than undeveloped a r e a s and induce more thunderstorms.

I n addition t o inadvertent modifications.

enhance p r e c i p i t a t i o n i n some regions.

3.2.2

c l o u d s a r e seeded t o

See Chapter .lo.

Evaporation from w a t e r s u r f a c e s

E v a p o r a t i o n i s commonly m e a s u r e d i n a n o p e n pan.

The w i d e l y - u s e d W e a t h e r

B u r e a u C l a s s A p a n i s 4 f t i n d i a m e t e r and 1 0 i n c h e s d e e p ( F i g . 3 . 2 8 ) .

It i s

48

Fig. 3 . 2 1 .

S t o r a g e r a i n gage w i t h s h i e l d .

F i g . 3.28.

Evaporation pan.

f i l l e d t o a d e p t h of 8 inches and t h e d e p t h i s measured d a i l y w i t h a hook gage. Evaporation i s t h e d i f f e r e n c e between r e a d i n g s , during the interval. refilled.

a d j u s t e d f o r any p r e c i p i t a t i o n

When t h e w a t e r l e v e l h a s r e c e d e d a n i n c h ,

t h e pan i s

An e v a p o r a t i o n s t a t i o n i n c l u d e s r a i n a n d t e m p e r a t u r e g a g e s . a n d

sometimes a n anemometer f o r measuring r i n d .

49 The r a t e o f e v a p o r a t i o n f r o m a p a n i s g r e a t e r t h a n t h a t f r o m a l a k e o r r e s e r v o i r because of t h e h e a t t r a n s f e r r e d t h r o u g h t h e pan w a l l s .

Although t h e

"pan c o e f f i c i e n t " t o a d j u s t annual pan e v a p o r a t i o n t o annual l a k e e v a p o r a t i o n i s c o n s i d e r e d t o b e a b o u t 0.7,

f o r s h o r t e r p e r i o d s i t v a r i e s c o n s i d e r a b l y and

cannot b e d e f i n e d re1 iably. O t h e r ways o f m e a s u r i n g w a t e r - s u r f a c e e n e r g y b u d g e t , and m a s s t r a n s f e r .

evaporation include w a t e r budget,

These methods r e q u i r e c o n s i d e r a b l e d a t a

c o l l e c t e d on a r e s e r v o i r f o r a y e a r or more. Water budget i s t h e s i m p l e s t . s t o r a g e a r e measured.

Inflow, outflow,

Water-surface

the o n l y unknown i n t h e water-budget

rainfall,

and change i n

e v a p o r a t i o n c a n be computed because i t i s equation.

R e l i a b i l i t y of t h e r e s u l t de-

p e n d s on t h e m a g n i t u d e of t h e e v a p o r a t i o n r e l a t i v e t o t h e m a g n i t u d e s o f t h e o t h e r e l e m e n t s : a s m a l l d i f f e r e n c e between two l a r g e numbers, some e r r o r ,

each s u b j e c t t o

tends t o be unreliable.

The e n e r g y - b u d g e t e q u a t i o n i n c l u d e s t h e e n e r g y i n p u t s a n d o u t p u t s , a l l o f which,

except evaporation,

c a n b e measured.

Data c o l l e c t i o n and a n a l y s i s a r e

d e s c r i b e d i n a c o m p r e h e n s i v e i n t e r a g e n c y p r o j e c t r e p o r t (U.S. Geol. S u r v e y , 1954). The m a s s - t r a n s f e r

E = Np ( e o

-

equation is

e,)

where E i s e v a p o r a t i o n , N i s t h e mass t r a n s f e r c o e f f i c i e n t .

p i s wind speed, and

eo and ea a r e s a t u r a t i o n vapor p r e s s u r e and a c t u a l vapor p r e s s u r e r e s p e c t i v e l y . M e a s u r e m e n t s o f w i n d s p e e d , and w a t e r and a i r t e m p e r a t u r e a r e r e q u i r e d .

The

c o e f f i c i e n t , N, m u s t b e d e r i v e d f r o m e v a p o r a t i o n m e a s u r e d b y a n o t h e r m e t h o d (See T u r n e r , 1966). 3.2.3

Temperature

D a i l y maximum and minimum a i r t e m p e r a t u r e s a r e o b t a i n e d a t many l o c a t i o n s by t h e N a t i o n a l Weather Service.

D e t a i l s of c o l l e c t i o n a r e g i v e n i n t h e i r Observ-

i n g Handbook No. 2 (NWS, 1 9 7 2 ) . 3.2.4

Snow accumulation

Snow f a l l i s r e p o r t e d a t w e a t h e r s t a t i o n s b u t t h e a c c u m u l a t i o n of snow on t h e ground o r d i n a r i l y is not.

Snow on t h e ground i s p o t e n t i a l r u n o f f which can be

f o r e c a s t i f t h e amount and c h a r a c t e r of t h e snowpack a r e known. t h e snowpack,

Measurement of

c a l l e d snow surveying, c o n s i s t s of measuring t h e d e p t h and w a t e r

c o n t e n t a t snow c o u r s e s ( F i g . 3.29).

A t u b e i s u s e d . t o e x t r a c t c o r e s of snow

f r o m t h e p a c k a t d e s i g n a t e d d i s t a n c e s a l o n g t h e l i n e m a r k i n g t h e snow c o u r s e . D e p t h is r e c o r d e d a t e a c h s a m p l i n g p o i n t and t h e c o r e i s w e i g h e d t o d e t e r m i n e t h e w a t e r c o n t e n t ( F i g . 3.30). D e p t h s and w a t e r c o n t e n t s a r e a v e r a g e d o v e r a l l

F i g . 3.29. Snow s u r v e y o r s a t a marker d e s i g n a t i n g o n e end o f a snow c o u r s e ( U . S . S o i l Conservation S e r v i c e ) .

Snow surveying: I n s e r t i n g t h e tube, reading t h e depth. and weighing F i g . 3.30. the tube w i t h the snow c o r e i n i t (U.S. S o i l Conservation S e r v i c e ) .

51 the sampling points to give the result.

Snow surveys are usually made near the

first of each of the spring months. In mountainous regions travel to a snow course by skis or snowshoes is time consuming;

if by helicopter the travel is expensive.

The number of visits can

be reduced by using a snow pressure pillow which is a flat flexible container filled with anti-freeze.

The pillow indicates the snow-water equivalent by the

pressure of the snow pack on the pillow.

Pressure readings are transmitted by

radio or satellite and transformed to water content by a previous calibration of the pillow (Ballison, 1981).

Soil Conservation Service (1972) describes snow-

surveying procedures in detail.

Use of snow survey results is described in

Chapter 11. 3.3

BASIN CHARACTERISTICS Knowledge of drainage basin characteristics is useful in understanding a

streamflow record and is a requirement in some methods of estimating flow c h a r acteristics at nngaged sites. Size of drainage area is the most common basin characteristic. basin is delineated on topographic maps and its area measured.

The drainage

In arid or

semiarid regions a major drainage basin may encompass an area which has no surface drainage; the contributing drainage area excludes that interior area. Drainage area may not be a good indicator of streamflow if the topographic and the ground-water divides are not coincident.

This disparity cannot be

easily quantified but its recognition will help to understand the measured flows or to estimate flows at ungaged sites. Basin topography influences runoff in several ways

-

steep slopes concentrate

the rainfall quickly and result in high flood discharges; flat slopes result in slow runoff, increased gronnd-water recharge, increased evapotranspiration, and consequently in decreased total runoff.

Basin topography is commonly quantified

by some approximation of the slope of the main channel.

An additional index is

the percentage of lakes and swamps in the basin. Vegetative cover can sometimes be quantified as the percentage of the area forested, or under cultivation.

In a natural basin, the vegetative cover de-

pends on climate and on soil characteristics. Soil characteristics determine the rate of infiltration of rainfall to the soil and thus affect the rate and amount of runoff.

The Soil Conservation

Service (1971) classifies each soil into one of four ranges according to infiltration rate. The geology of a basin affects the rate of runoff',

the losses or gains along

the channels, and especially the low-flow characteristics. Knowledge of the geology as i t affects the water resource may be very useful even though i t is only qualitative.

52 P r e c i p i t a t i o n usually i s considered a basin characteristic. p r e s s e d a s mean annual p r e c i p i t a t i o n ,

t h e 12-hour s t o r m p r e c i p i t a t i o n a t 50-year a p p r o p r i a t e t o a p a r t i c u l a r problem.

I t c a n b e ex-

some measure of s t o r m i n t e n s i t y such a s r e c u r r e n c e i n t e r v a l , or i n o t h e r ways

Likewise,

monthly mean t e m p e r a t u r e s a r e

b a s i n c h a r a c t e r i s t i c s in t h a t t h e y a r e i n d i c a t o r s of p o t e n t i a l e v a p o r a t i o n and t r a n s p i r a t i o n r a t e s and of whether p r e c i p i t a t i o n w i l l be snow and whether i c e w i l l form i n s t r e a m s .

Stream channel geometry,

esthetic character,

stability,

and s u i t a b i l i t y f o r

f i s h a n d w i l d l i f e h a b i t a t a r e useful d e s c r i p t o r s a l t h o u g h q u a n t i f i c a t i o n i s somewhat s u b j e c t i v e . 3.4

TRANSMISSION OF HYDROLOGIC DATA Conventionally, t h e s t a g e d a t a observed o r recorded a t a gaging s t a t i o n i s

o b t a i n e d when t h e hydrographer v i s i t s t h e s t a t i o n , a t monthly or l o n g e r i n t e r vals.

T h i s frequency of c o l l e c t i o n i s adequate i f t h e d a t a a r e t o be used f o r

w a t e r r e s o u r c e s t u d i e s or f o r p r o j e c t design.

But f o r w a t e r management p u r p o s e s

t h e d a t a may be needed immediately, or i n s o - c a l l e d " r e a l time."

B a s i c e l e m e n t s f o r a s a t e l l i t e d a t a - c o l l e c t i o n s y s t e m (From U.S. F i g . 3.31. Geological Survey). V a r i o u s s y s t e m s f o r t r a n s m i t t i n g d a t a d a i l y or m o r e f r e q u e n t l y u t i l i z e phone l i n e s o r r a d i o s .

Xn t h e l a s t few y e a r s automated s a t e l l i t e t e l e m e t r y h a s

become a p r a c t i c a l means of p r o v i d i n g water-data t i o n w i t h i n t h e t i m e frame needed.

u s e r s w i t h h y d r o l o g i c informa-

S a t e l l i t e data-collection

s y s t e m s use e a r t h -

o r b i t i n g s a t e l l i t e s t o r e l a y d a t a from c o l l e c t i o n s i t e s t o r e c e i v i n g s t a t i o n s . The system c o n s i s t s of s e n s o r s ,

small radios called data-collection

platforms.

53 satellites, earth receiving sites, and a data processing and distribution system.

See Shope and P a u l s o n (1981) and F l a n d e r s (1981).

T h e system is illus-

trated in Figure 3.31. REFERENCES Bailey, J.F. and Ray, H.A., 1966, Definition of stage-discharge relation in natural channels by step-backwater analysis: U.S. Geol. Survey Watersupply Paper 1869-A, 24 p. Barnes, H.H., Jr., 1967, Roughness characteristics of natural channels: Geol. Survey Water-Supply Paper 1849, 213 p. Barnes, H.H., Jr. and Davidian. J., 1978, Indirect methods Herschy, ed., New York. John Wiley and Sons.

U.S.

Hydrometry, R.W.

Barnett, P.R. and Mallory, E.C., Jr., 1971, D e t e r m i n a t i o n of m i n o r elements in w a t e r b y e m i s s i o n spectroscopy: U.S. Geol. Survey Techniques of WaterResources Investigations, Book 5, Chapter A2, 31 p. Bodhaine, G.L., 1968, M e a s u r e m e n t of p e a k discharge at culverts b y indirect methods: U.S. Geol. Survey Techniques of Water-Resources Investigations, B o o k 3, Chapter A3. 60 p. Buchanan, T.J., 1964, Time of travel of soluble contaminants in streams: of Sanitary Engineering Division, ASCE, Vol. 90. No. SA3, 12 p.

Jour.

Buchanan, T.J. and Somers, W.P., 1969, Discharge m e a s u r e m e n t s at gaging stations: U.S. Geol. Survey Techniques of Water-Resources Investigations, Book 3, Chapter A8, 6 5 p. Colby. B.R., 1963, P l u v i a l s e d i m e n t s - A s u m m a r y of source, transportation, deposition, and m e a s u r e m e n t of sediment discharge: U.S. Geol. Survey Bull e t i n 1181-A, 4 7 p. 1981, Debris f l o w s i n s m a l l m o u n t a i n stream Costa, J.E. and Jarrett, R.D., channels of Colorado and their hydrologic implications: Bulletin of the Assoc. of Engineering Geologists, Vol. xviii, No. 3, August 1981. Dalrymple, T. and Benson, M.A., 1967, M e a s u r e m e n t of p e a k discharge b y the slope-area method: U.S. Geol. Survey Techniques of Water-Resources Investigations, Book 3, Chapter A2, 12 p. Davidian, J., 1984, C o m p u t a t i o n of water-surface profiles: U.S. Geol. Survey Techniques of Water-Resources Investigations, Book 3, Chapt. Al5. 1976, A technique for estimating t i m e of Eikenberry, S.E. and Davis, L.G., travel of water in Indiana streams: U.S. Geol. Survey Water Resources Investigations 9-76. 3 9 p. Flanders, A.F., 1981, Hydrological data transmission: W o r l d Meteorological Organization, Operational Hydrology Report No. 14, WMO-No. 559, 3 4 p., Geneva, Switzerland. Goerlitz, D.F. and Brown, E., 1972, M e t h o d s for analysis of organic substances in water: U.S. Geol. Survey Techniques of Water-Resources Investigations, B o o k 5, Chapter A3, 40 p.

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Herschy,

Greeson, P.E.. Elke, T,A., Irwin. G.A., Lium, B.W., and Slack, K.V., 1977, Methods for collection and analysis of aquatic biological and microbiological samples: U.S. Geol. Survey Techniques o f W a t e r Resources Investigations, B o o k 5, Chapter A4, 3 3 2 p.

54 Guy, H.P. and Norman, V.W.. 1976, Field methods for measurement of fluvial sediment: U.S. Geol. Survey Techniques of Wa t er-Resources Investigations, Book 3. Chapter C2, 5 9 p. Hem. J.D.. 1972. Study and interpretation of the chemical characteristics of natural water: U.S. Geol. Survey Water-Supply Paper 1473, Second Edition, 363 p. Hubbard. E.F.. Kilpatrick, F.A., Martens, L.A.. and Wilson, J.F.. Jr., 1982, Measurement of time of travel and dispersion in streams by dye tracing: U.S. Geol. Survey Techniques of Water-Resources Investigations, Book 3. Chapt. A9. 44 p. Hulsing. H., 1968, Measurement of peak discharge at dams by indirect methods: U.S. Geol. Survey Techniques of Water-Resources Investigations, Book 3, Chapter A5. 29 p. Kennedy, E.J., 1983. Discharge ratings at gaging stations: U.S. Geol. Survey Techniques of Water-Resources Investigations, Book 3, Chapt. A10. Kilpatrick. F.A. and Cobb. E.D.. 1984. Measurement of discharge using tracers: U . S . Geol. Survey Open-File Rept. 84-136, 73 p. Laenen, A. and Smith, W., 1982. Acoustic systems for the measurement of streamflow: U.S. Geol. Survey Open-File Rept. 82-329, 45 p. Matthai. H.F.. 1968, Measurement of peak discharge a t width contractions by indirect methods: U.S. Geol. Survey Techniques of Water-Resources Investigations, Book 3, Chapter A4. 44 p. NWS,

1972, Substation observations, National Weather Service Observing Handbook No. 2: National Weather Service, Data Aquisition Division, Office of Meteorological Operations, Silver Spring, Md.

Peterson, H.V.. 1962. Hydrology of small watersheds in western States: Geol. Survey Water Supply Paper 1475-1, 137 p.

U.S.

Porterfield, G., 1972. Computation of fluvial-sediment discharge: U.S. Geol. Survey Techniques of Water-Resources Investigations, Book 3 . Chapter C3. 66 P. Rallison. R.E.. 1981, Automated system for collecting snow and related hydrological data in mountains of western United States: Hydrological Sciences Bulletin, Vol. 26, No. 1, March 1981, p 83-89. Rantz, S.E.. 1982. Measurement and computation of streamflow: U.S. Water-Supply Paper 2175. 631 p.

Geol. Survey

Riggs. H.C., 1976, A simplified slope-area method for estimating flood discharges in natural channels: U.S. Geol. Survey Jour. of Research, 4 (3). p 285-291. Shope. W.G. and Paulson, R.W., 1981, Data collection via satellite for water management: Transportation Engineering Journal, ASCE, Vol. 107, No. TE4, July 1981. p 445-455. Simmons, C.E., 1976. Sediment characteristics of streams in the eastern Piedmont and western Coastal Plain regions of North Carolina: U.S. Geol. Survey Water-Supply Paper 1798-0. p 10-14. Skougstad. M.W.. Ed., 1979, Methods for determination of inorganic substances in water and fluvial sediments: U.S. Geol. Survey Techniques of Water-Resources Investigations, Book 5 . Chapter Al. 626 p. Smith, W., Hubbard, L.L.. and Laenen. A., 1971, The acoustic streamflow-measuring system on Columbia River at The Dalles. Oregon: U.S. Geol. Survey OpenFile Report, Portland, Oregon.

55 Smoot, G.F. and Novak, C.E.. 1969, M e a s u r e m e n t of discharge b y the moving-boat method: U.S. Geol. Survey Techniques of Water-Resources Investigations, Book 3, Chapter All, 2 2 p. Soil Conservation Service, 1971, Hydrology, SCS National Engineering Handbook, Section 4: Soil Conservation Service, U.S. Dept. of Agriculture, Washington, D.C. Soil Conservation Service, 1972, Snow survey and water-supply forecasting: SCS National Engineering Handbook., Section 22, Soil Conservation Service. U.S. Dept. of Agriculture, Washington. D.C. Stevens. H.H.. Jr., Ficke, J.F., and Smoot. G.F., 1975. W a t e r temperature influential factors, field measurement. and data presentation: U.S. Geol. 65 Survey Techniques of Water-Resources Investigations, Book 1, Chapter D1, P. Thatcher. L.L., Janzer, V.J., and Edwards. K.W.. 1977. Methods for determination of radioactive substances in water and fluvial sediments: U.S. Geol. Survey 95 p. Techniques of Water-Resources Investigations, Book 5. Chapter AS, Turner, J.F., Jr., 1966, Evaporation study i n a h u m i d region, Lake Michie, North Carolina: U.S. Geol. Survey Prof. Paper 272-6. U.S.

Geological Survey, 1954. W a t e t l o s s investigations Volume 1 - Lake Hefner studies: U.S. Geol. Survey Prof. P a p e r 269.

Ed., 1975, Sedimentation engineering: Vanoni, V.A.. Practice, 745 p.

ASCE Manual of Engineering

White, K.E., 1978, Dilution methods & H y d r o m e t r y by R.W. Pork, John Wiley and Sons.

Herschy, Ed.:

New

Wilson, J.F., Jr.. 1968, Time of travel measurements and other applications of dye tracing: International Assoc. of Scientific Hydrology Publ. NO. 76, Bern. p 252-262. WMO, 1980, Manual on stream gauging: World Meteorological Organization Operational Hydrology Report No. 13. W M O - No. 519. Vol. 2, Geneva. Switzerland.