US Army Corps of Engineers Hydrologic Engineering Center

Feasibility Analysis in Small Hydropower Planning August 1979 Approved for Public Release. Distribution Unlimited. TP-65

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4. TITLE AND SUBTITLE Feasibility Analysis in Small Hydropower Planning

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6. AUTHOR(S) Darryl W. Davis, Brian W. Smith

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7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) US Army Corps of Engineers Institute for Water Resources Hydrologic Engineering Center (HEC) 609 Second Street Davis, CA 95616-4687

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12. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release; distribution is unlimited. 13. SUPPLEMENTARY NOTES Presented at the Conservation and Utilization of Water and Energy Resources Conference, American Society of Civil Engineering, San Francisco, California, 8-11 August 1979 14. ABSTRACT The Hydrologic Engineering Center, Corps of Engineers, has prepared a manual entitled "Feasibility Studies for Small Scale Hydropower Additions". The manual provides technical data and procedural guidance for the systematic appraisal of the viability of potential small hydropower additions and focuses upon the concepts, technology, and economic and financial issues unique to these additions. This paper presents the significant findings and conclusions that became evident from the studies performed during preparation of the manual. 15. SUBJECT TERMS small scale hydropower, feasibility, reconnaissance, planning

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b. ABSTRACT U

c. THIS PAGE U

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Feasibility Analysis in Small Hydropower Planning

August 1979 US Army Corps of Engineers Institute for Water Resources Hydrologic Engineering Center 609 Second Street Davis, CA 95616 (530) 756-1104 (530) 756-8250 FAX www.hec.usace.army.mil TP-65

Papers in this series have resulted from technical activities of the Hydrologic Engineering Center. Versions of some of these have been published in technical journals or in conference proceedings. The purpose of this series is to make the information available for use in the Center's training program and for distribution with the Corps of Engineers. The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products.

FEASIBILITY ANALYSTS IN SMALL HYDROE'OWER PLANNING l

a Darryl W. Davis, !<ember, ASCE

Br ian W. smith,' Member, ASCE

The Kydrologic Engineering Center, Corps of Engineers, has prepared a

manual e n t i t l e d "Feasib. i l i ty S t u d i e s f o r Small S c a l e IIydropower Additions".

The manual provides t e c h n i c a l d a t a and procedural guidance f o r t h e sys temat ic

a p p r a i s a l of the v i a b i l i t y of p o t e n t c a l small hydropower a d d i t i o n s and

focuses upon the concepts , technology, and economic and f i n a n c i a l i s s u e s

unique t o these add i t i ons . The manual, designed t o a i d i n the performance

of reconngissance s t u d i e s (should a f e a s i b i l i t y s tudy b e performed?) and

f e a s i b 6 l i t y s tudi ,es (should a n investment commitment b e made?) , was developed

f o r u s e 6 y pub l i c agencies (federal , state, and l o c a l ) , pub l i c and p r i v a t e

u t i l i t i e s , and p r i v a t e i nves to r s .

The manual i nc ludes d a t a and d2scussions on the t o p i c a l s u b j e c t s of

c o s t escalat-lon I n economic and f%nanc ia l a n a l y s i s , f e a t u r e component

s e l e c t i o n f o r reconnaissance and f e a s i b i l i t y levels of s tudy , and t i m e ,

c o s t s , and r e sou rces r equ i r ed t o perform the This paper

p r e s e n t s tke s igni f i , can t f i nd ings and conclus ions t h a t became evident from

t h e s t u d i e s performed during prepara t ion of the manual CIaC, 1979).

DEFINITION OF S W L HYDROPOWER

Small hydro p r o j e c t s i nc lude i n s t a h l a t i o n s t h a t have 15,000 kV o r less

capac i ty . "Small hydro" and "low head hydro" a r e n o t synonomous . Small

1 1.

Presented a t t h e Conservation and U t i l i z a t i o n of Water and Energy Xesources Conference, American Soc ie ty of Civil Engineers, 8-11 August, 1979, San Francisco, Ca l i fo rn i a .

a Chief, Planning Analysis Branch, The Rydrologic Engineering Center, U .S . Amy Corps of Engineers, Davis, Ca l i fo rn i a , 95616.

Hydraul ic Engineer, Planning Analysis Branch, The Hydrologic Engineering Center, U.S. Army Corps of Engineers, Davis, Ca l i fo rn i a , 95616.

hydro as def ined has been an informal breaking p o i n t used f o r va r ious f e d e r a l

and o t h e r agency s t a t i s t i c a l t a h u l a t k n s and informal communi.cations . The

concept has no@ Seen def ined by l a w (YL 9 5-617, 95 th Congress 1978) t o be

15,000 kK f o r purposes of s p e c i a l handx-ing f o r l i c e n s i n g , l oans , implementa-

t i o n i n c e n t i v e s , and o t h e r promotZonal programs. Low head hydro is a term

a s s o c i a t e d w i t h a r e s e a r c h and devel.opment program managed by t h e Department

of Energy- t h a t i s designed t o advance the technology f o r gene ra t ing hydro-

power from sites w t t h heads of less than 20 meters (66 f e e t ) .

FACTORS' TMPORTANT FOR FEASTBILT,TY

The reasons under ly ing t h e major n a t i o n a l a t t e n t i o n t h a t i s focused on

smal l hydro is important i n e s t a b l i s h i n g the conceptual Ease f o r e s t a b l i s h -

i ng a f e a s i f j i l i t y methodology. S inply s t a t e d , they s e e m t o be: the n a t i o n a l

d e s i r e t o move t o energy independence, the c u r r e n t n a t i o n a l concern f o r

r e sou rce conserva t ion , t h e potenti.a'l f o r qu ick r e s u l t s from puG13.c and

p r i v a t e e f f o r t s Can i n c r e a s i n g l y rare commodtty- i n today ' s wor ld) , and t h e

demand f o r non f l r m energy, p r e s e n t l y valued i n many a r e a s a t 1 5 t o upwards

of 40 m t l l s per k.5lomtt-hour a s compared t o 1 t o 2 m i l l s pe r kf lowat t -

hour several years ago. The c k a r a c t e r of small hydro is such t h a t t h e

marketable output w i l l most o f t e n only be energy wi th l i t t l e , i f any, depen-

d a b l e capac i ty . This means t h e va lue of s m a l l hydropower w i l l b e p r imar i ly

due t o f u e l and o t h e r ope ra t ing c o s t sav ings and n o t due t o o f f s e t t i n g t h e

need f o r new power p l a n t s t o supply capac i ty .

The f e a s i b i l i t y of p r o j e c t s i s expected t o b e q u i t e s e n s i t i v e t o s i t e

s p e c i f i c cond i t j ons , e.g., t h e q u a n t i t y of po+er produced w i l l n o t l i k e l y

support an ex tens ive a r r a y of a n c i l l a r y f e a t u r e s such a s long t ransrnjss ion

l i n e s , acces s roads, o r s i g n i f i c a n t s i te p repa ra t ion , e t c . The n a t u r e o f

t h e market a r e a load c h a r a c t e r i s t i c s and p r e s e n t gene ra t ing f a c i l i t i e s

s e r v i c i n g the load a r e c r i t i c a l elements i n va lu ing power output . Areas

served wi th major f o s s i l f u e l base p l a n t s o r systems w i t h h igh ope ra t ing

c o s t p l a n t s , ope ra t ing a t the margin w i l l be more a t t r a c t i v e f o r small hydro

development. A s i g n i f i c a n t i s s u e of p r o j e c t f e a s i b i l i t y is t h a t i n v e s t i g a t i o n ,

design, c o n s t r u c t i o n management, admin i s t r a t ron and c o n t i n g e ~ l c i e s ( t he non-

hardware elements of a p r o j e c t ) are a major c o s t b ~ r d e n , F igure 1 schemat ica l ly

MINIMUM CIVIL FEATURES COSTS

C IV IL FEATURES s INDIRECTS 30% ACCESSORY

INTEREST-DURING CONSTRUCTION 10%

I MAXIMUM CIVIL FEATURES COSTS

Figure 1. Range o f C i v i l Features Costs (Vol . 6 HEC, 1979)

L l l u s t r a t e s th.e c o s t elements i n small hydro p r o j e c t s .

PZANRTNG STUDIES

Severa l types of s t u d i e s vary ing i n scope, d e t a i l , and intended c l i e n t

a r e performed t o determine t h e d e s i r a b i l t t y of pub l i c and p r i v a t e implementa-

t i o n of hydropower proposa ls . Th i s manual h a s adopted t h e s tandard sequence

of p recons t ruc t ion s t u d i e s commonly followed i n p r i v a t e and i n t e r n a t i o n a l

p r a c t f c e . TIiey a r e ' ~ e c ~ n n a i s s a n c e ' ~ (should a f e a s i b i l i t y s tudy be performed?),

' Y e a s i b i l i t y " (should an investment commitment b e made?) , and " d e f i n i t e plan' '

cthe c o l l e c t i v e group of s tud i ,es that a r e performed between an implementation

commitment and cons t ruc t ton i n i t i a t i o n t h a t r e s u l t i n permit a p p l i c a t i o n s ,

p repa ra t ion of marketing agreements and f i n a n c i a l arrangements, and d e f i n i t i o n

of des ign parameters) . The manual is designed t o a i d i n t h e execut ion of

the reconnaissance and P e a ~ ~ b i l i t y s t u d i e s . The manual d e f i n e s a reconnais- 11 sance s tudy a s . . . a p re l imina ry f e a s 2 6 t l i t y s tudy designed t o a s c e r t a i n

I1 whether a f e a s i h i l t t y s tudy is warranted: and f e a s i b i l i t y s tudy as . . . an

i n v e s t i g a t inn performed t o formula te a hydropower pro j e c t and d e f i n i t i v e l y

a s s e s s i t s d e s i r a B i 1 i t y f o r tmplementation. "

RE CObTNAIS S ANCE 5 TUDY

The execut ion of a f e a s i b i l i t y s tudy can be a s i g n i f i c a n t investment i n

t i m e and resources suggeszing t h a t a dec i s ion t o proceed wi th a s tudy should

be based on a f i n d i n g t h a t a p o t e n t i a l l y v i a b l e p r o j e c t proposal w i l l b e

forthcoming. The reconnaissance s tudy is designed t o reduce t h e p o t e n t i a l

chance of a subsequent unfavorable f e a s i b i l i t y f i nd ing and naximize t h e

p o t e n t i a l f o r i d e n t i f y i n g and moving forward t h e attractive p r o j e c t s . The

reconnaissance s tudy i s a r e l a t i v e l y complete smal l s c a l e f e a s i b i l i t y s tudy

i n which t h e i s s u e s expected t o b e important a t t h e f e a s i b i l i t y s t a g e a r e

r a i s e d . The f i n d i n g of a reconnaissance s tudy should b e either a p o s i t i v e

recommendation t o proceed wi,th a f e a s i b i l i t y s tudy whi,ck would inc lude a

s tudy p l an and method of accompl.isIiment, o r a recomaendation t o te rmina te

f u r t h e r i n v e s t i g a t i o n s .

P r o j e c t FormuLat i o n

The s t r a t e g y %or performing a reconnaissance s tudy is f i r s t t o perform

a pre l iminary economic a n a l y s i s and then i d e n t i f y and a s s e s s t h e i s s u e s

t h a t may b e c r i t i c a l t o inp lanenta t ion . The components i d e n t i f i e d as

important in reconnaissance s t u d i e s a r e shown i n F igu re 2. The forraulat2on

of p r o j e c t f e a t u r e s and de termina t ton of c o s t s w a s determined t o b e a

cr i t ical and major task . me recomnencled p r o j e c t formula t ion s t r a t e g y is

t o s e l e c t several i n s t a l l e d c a p a c i t i e s , say a t 35%, 25% and 35% f low

exceedance v a l ~ e s , and c a r r y these through the pre l iminary ecsnomfc a n a l y s i s .

The procedures devel.oped f o r p e r f o r m l ~ g the c o s t escimates f o r eonstruct i .on,

s i t e . acquisi , t ion, ope ra t ion and ma3ntenance, and engiaser ing and administra--

t5an f o r tIze r"easih2li'cy szudy were judged t o be too d e t a i l e d f o r a

reconnaissance s tudy. To f a c i l i t a t e reconnaissance e s t ima te s , t h e information

f o r the f e a s i b i l i t y a n a l y s i s was consol ida ted i n t o one c h a r t and t a b l e .

F igu re 3 provides a b a s i s f o r e s t ima t ing t h e major s h a r e of c o n s t r u c t i o n

c o s t s f o r i t e m s t h a t a r e governed by c a p a c i t y and head, e.g. , t u r b i n e and

genera tor , powerhouse, and suppor t ing e l ec t r i ca l /mechan ica l equipment. The

f i g u r e was developed by s tudying t h e gene ra to r and powerhouse c o s t s f o r a

v a r i e t y of t u r b i n e types f o r a complete set of headlcapac i ty va lues . Table 1

con ta ins reconnaissance c o s t f a c t o r s f o r penstock, t a i l r a c e , switchyard

equipment, and t r a n m i s s i o n l i n e . The u s e r i s caut ioned t h a t t h e l e a s t

c o s t c r i t e r i a governed so t h a t s i te i s s u e s of space and conf igu ra t ion , and

gene ra t ion i s s u e s of performance ranges were n o t considered. The d a t a ,

however, should be adequate f o r reconnaissance e s t ima te s . An a d d i t i o n a l

a l lowance of up t o 20% should b e added t o the c o s t determined t o cover

investment items t h a t a r e not incorpora ted in the c h a r t and t a b l e such a s

l and acqu i s t i ons , acces s roads, and s p e c i a l c o n t r o l equipment. P r o j e c t s

approaching t h e upper limits of c a p a c i t y (l5W) probably warrant u s ing the

more d e t a f l e d and s p e c i f i c c h a r t s i n the manual even f o r the reconnaissance

estimate,

Stnce reconnaissance c o s t estimates are a l s o needed f o r t h e nonphysical

works c o s t items, a n al lowance f o r unforseen conti .ngencies ranging from

10% t o 20% should be added t o t h e sum of t h e c o n s t r u c t i o n c o s t , t h e v a l u e

EFFECTIVE HEAD ( F T )

I . Estimated costs are based upon a typical or standardized turbine coupled to a generator either directly or through a speed increaser, depending on the type turbine used.

2. Costs include turbine/generator and appurtenant equipment, station electric equipment, miscellaneous powerplant equipment, powerhouse, powerhouse excavation, switchyard civil works, an upstream slide gate, and construction and instal lation.

3. Costs not included are transmission 1 ine, penstock, tailrace con- struction,. swi tchyard equipment.

4. Cost base July 1978.

5. The transition zone occurs as unit types change due to increased head.

6. For a Multiple Unit powerhouse, additional station equipment costs

Figure 3. Power Features Cost - Reconnaissance

[Vol. 1 H E C , 1979)

TABLE 'I

MISCELLANEOUS RECONNAISSANCE ESTIMATE COSTS*

PENSTOCK COST - --

E f f e c t i v e Head (Ft ) 1.0 2 0 5 0 100 200 300

Cost Index (CI) 960 480 200 11.0 55 35

I n s t a l l e d Cost = Cl x Penstock Length(f t ) x I n s t a l l e d Capacity(MW)

TAILRACE COST

Construction Cost = $1.5,000 f ixed p lus $200 per l i n e a l foo t

SWITCHYARD EOUIPMENT COST

(Thousand Dol lars)

P lan t Transmission Voltage

Capacity ---- 13.8 34.5 6 9 11 5

I M W 5 0 60 -- -- 3 MW 85 100 120 175

5 MW 110 125 150 210

10 MW 150 170 210 280

1 5 MW 185 220 250 320

TRANSMISSION LINE COST

(Thousand Doll.ars)

Plant Miles of t ransmiss ion l i n e

Capacity 1 - 2 5 10 15 --

* (Vol . 1 HEC, 1979)

depending upon a judgement a s t o t h e u n c e r t a i n t i e s . I n d i r e c t c o s t s of

25% a r e recommended t o b e added f o r i n v e s t i g a t i o n , management, engzneering,

and admin i s t r a t ion c o s t s t h a t are needed t o implement t h e p r o j e c t and

cont inue i ts service. 0perati.on and maintenance c o s t s can va ry cons iderably

depending on p re sen t s t a f f resources of t h e pro j e c t proponent, t h e site

proximity t o o t h e r sites, and the intended degree of on - s i t e ope ra t ion

requirements . An annual va lue of 1.5% of t o t a l c o s t s i s suggested a s a b a s e

va lue ; however, tke v a l u e used sfiould n o t b e less than a b a s e va lue , suggested

as $20,000 p e r year and may range upwards of 4% i f the p r o j e c t proponents

can n o t e f f i c i e n t l y i n t e g r a t e the p lan t i n t o their work program.

Power Values -

The de termina t ion of va lue of power was an i t e m c a r e f u l l y considered

dur ing p repa ra t ion of the manual. The power va lue needed Is the va lue t h a t

t h e p r o j e c t proponent could reasonably expect t o r e c e i v e f o r the s a l e

of t h e genera ted energy and that of the dependab1.e capacr ty , i f any ex5sts.

A suggested procedure is t h a t reconnaissance va lues B e adopted from va lues

s o l i c i t e d f r o n t h e r e g i o n a l Federa l Energy Regulatory Commission (FERC) o f f i c e

i n t h e c a s e of p o t e n t l a l sale t o u t l l . i t i e s , municipal organizat2,ons and

coope ra t ives , o r b e e x t r a c t e d from e x i s t i n g r a t e shcedules (avaluable from

l o c a l u t i l i t y o f f i c e s ) i n t h e c a s e of p o t e n t i a l sale t o a p r i v a t e i n d u s t r i a l

buyer. A benchmark va lue t h a t can o f t e n be used t o va lue energy is t h e f u e l

replacement c o s t t h a t i s r epor t ed by u t i l i t i e s t o t h e FERC Regional Of f i ce s .

A generous va lue i n t h e range of 20 t o 40 m i l l s per kWI.1 i s considered

r easonab le i n l i g h t of p r e s e n t l y e s c a l a t i n g f u e l and ope ra t ion c o s t s .

Economic F e a s i b i l i t y

Economic F e a s i b i l i t y i s p o s i t i v e when t h e b e n e f i t s exceeds t h e c o s t s .

The manual encourages adoption of t h e I n t e r n a l Rate of Return method of

c h a r a c t e r i z i n g p r o j e c t f e a s i b i l i t y . The I n t e r n a l Rate of Return i s t h e

d i scoun t rate a t which t h e b e n e f i t s and c o s t s a r e equal , e.g., t h e d iscount

r a t e a t which the Genef i t t o c o s t r a t i o is u n i t y . Use of the method avoids

the need a t t h e reconnaissance s t a g e t o adopt a d i scount r a t e and a l s o provides

a n a r r a y of economic f e a s i b i l i t y r e s u l t s . An example computation and

d i s p l a y is included in Figure 4. To perform t h e a n a l y s i s s e v e r a l d i scoun t

r a t e s a r e s e l e c t e d and the t o t a l investment c o s t i n annual ized f o r each

r a t e and added t o the annual opera t ion and maintenance c o s t t o o b t a i n t h e

t o t a l annual c o s t . The benef i.t is computed on an annual b a s i s by mul t ip ly ing

the y e a r l y genera t ion by the v a l u e of energy. A b e n e f i t t o c o s t r a t i o is

determined f o r each t o t a l annual ized c o s t which i s then p l o t t e d r e l a t i v e

t o its r e s p e c t i v e d iscount r a t e . A curve is drawn connect ing t h e p l o t t e d

p o i n t s and the Xnternal Rate of Return i s t h e d iscount r a t e where t h e curve

i n t e r s e c t s t h e l i n e r ep re sen t ing a b e n e f i t t o c o s t r a t i o of u n i t y Csee

example) .

FEASIB1LI.TY STUDY

The f e a s i b i l i t y s tudy is designed t o formula te a v i a b l e small hydro

p r o j e c t , develop an implementation s t r a t e g y , and provide the b a s i s f o r an

impl.ementation commitment . The a d d i t i o n of small hydropower genera t ion t o

an e x i s t i n g f a c i l i t y is, w i t h few except ions, a s i n g l e purpose p r o j e c t

planning t a s k . The s i g n i f i c a n t l e g a l , i n s t i t u t i o n a l , engineering, environ-

mental , marketing, economic and f i n a n c i a l a spec t s a r e t o b e i d e n t i f i e d ,

i n v e s t i g a t e d , and d e f i n i t i v e l y a s se s sed i n suppor t of an investment dec i s ion .

The o b j e c t i v e is t o formula te a power a d d i t i o n p r o j e c t that i s economically

a t t r a c t i v e and c o n s i s t e n t w i t h modern concepts of resource planning and

management. The f i n d i n g s of a f e a s i b i l i t y s tudy should be whethex o r n o t

a commitment t o implementation i,s warranted, and should the f i n d i n g b e

p o s i t i v e , d e f i n e t h e s t e p s needed t o a s s u r e implementation.

The s e l e c t i o n of t h e i n s t a l l e d capac i ty , t h e number of u n i t s , and t h e

suppor t ing a n c i l l a r y phys i ca l works a r e t h e s p e c i f i c o b j e c t i v e of p r o j e c t

formula t ion . The t a r g e t of small hydro p r o j e c t formulat ion is t o develop

one o r more proposals t h a t have t h e g r e a t e s t economic va lue c o n s i s t a n t

w i t h t h e a r r a y of c o n s t r a i n t s t h a t modify t h e a t t r a c t i v e n e s s of a pu re ly

economic formulati,on. Twa i s s u e s were s ing led o u t f o r expanded d i scuss ion

i n t h e f e a s i b i l i t y s tudy sect i ,on of the manual. hey were ref inement of

a l t e r n a t i v e s and development of c o s t s f o r b o t h the economic and f i n a n c i a l

a n a l y s i s .

PLANT CHARACTERISTICS:

RUN OF RIVER

Head = 9 0 f e e t Penstock = 115 f e e t Capac i t y = B MW Transmiss ion L i n e = 2.5 mi 1 e s Q 34.5 kV E f f i c i e n c y = 90% Economic L i f e = 50 y e a r s Dependabl e Capaci t y = 0 MW E v a l u a t i o n Date = J u l y 19z9 Tai 1 race = 250 f e e t Average Year1 y Energy Generated = 35 x 1 0 kwh

INVESTMENT COST: ($1,000)

Turb ine . Genera tor and C i v i 1 ( F i g u r e 4-21 2,000

A d d i t i o n a l S t a t i o n Equipment (Mu1 t i - U n i t ) None Requ i red

Penstock (Tab1 e 8-21 (128 x 115 x 8 ) 118

T a i l r a c e ( T a b l e 4-21 (15 ,000) + I200 x 250) 65

Swi t c h y a r d Equipment ( T a b l e 9-21 ( 8 MW Q 34.5 kV) 152

Transmission L i n e ( 8 HW O 2.5 mi 1 es) 105

Darn R e h a b i l i t a t i o n [ I n t e g r i t y ) None Requi red

Other (Access, F i sh Passage, Mi s c e l laneous Si t e C o n s t r u c t i o n ) None Requ i red

SUBTOTAL 2.440

E s c a l a t i o n ( J u l y 78 t o J u l y 7 9 - F i g u r e 6-1, Vol . VI - Ra t i o : 2.5212.28) 2.697

Con t i ngenc ies a t 10%-20% (Used 15%) 40 5

SUBTOTAL 3.102 I n d i r e c t 25% 776

TOTAL INVESTMENT COST 3.877

ANNUAL COST: ($1,000)

Annua l ized lnves tment Cost i s a f u n c t i o n o f d i s c o u n t r a t e and economic l i f e o f a p r o j e c t and i s computed by m u l t i p l y i n g t h e T o t a l lnves tment Cost by t h e C a p i t a l Recovery F a c t o r f o r t h e d i s c o u n t r a t e and economic l i f e se lec ted . See T a b l e Below

Opera t i on and Main tenance (O&M) Cost = ($20.000 Minimum o r 1.5%-4%) (Used 3 % ) 116

TOTAL. ANNUAL COST (Sum o f Annua l i zed lnves tment Cost and O&M Cos t ) = See T a b l e Below

BENEFIT ESTIMATE:

Capac i ty Benef i t [Dependable Capaci t y x Va lue o f Capac i ty ) = None

Energy B e n e f i t (Average Annual Energy Generated x Value o f Energy) = See Tab le Below

TOTAL ANNUAL BENEFIT (Sum o f C a p a c i t y B e n e f i t and Energy B e n e f i t ) = See T a b l e Below

I NOTES:

C O S T A N D B E N E F I T C O M P U T A T I O N T A B L E

t a l Recovery Factor x To ta l lnvestment Cost ($3.8771.

' ~ n n u a l i zed lnvestment Cost +. O&M Cost (5116).

' ~ o t a l Annual Cost f Average Annual Energy Generated (35x106kWh).

'Average Annual Energy Generated (35x106kWh) x Value o f Energy (taken as 22 m i 1 ls/kWh) p lus the Capaci t y Benef i t (equal t o zero f o r t h i s exarnpl e l .

'Total Annual Bene f i t ($770) - Tota l Annual Cost.

6Total Annual Benef i t ($770) f Total Annual Cost.

I

I Dl SWUNT ( lNTEREsT)

RATE (%)

12

14

16

18

20

~ i g u r e 4. ~econnaissance economic feasibility example (Vol 1,HEC 1979)

11

CAPITAL RECOVERY

-12042

. l W 2 0

.I6010

-18005

-20002

ANNUALIZED

iNvgGpT ($1 ,000)

467

544

621

698

775

TOTAL ANNuAk

COST ($1 ,000)

583

660

7 37

8 14

891

BRE*I( EVM ENERGY V A U E ~ (Mi 1 l s / k W

16.7

18.9

21.1

23- 3

25-5

B/C

1.32

1.17

1.04

0.95

0-86

TOTAL

($1 ,000)

770

77 0

770

770

770

N ET B ~ E F I T5 ($1 ,000)

187

110

33

4 4

-121

12 14 16 18 20

DISCOUNT RATE ( % ) ( I n t e r e s t R a t e )

r --- - ---

INTERNAL RATE OF RETURN:

The Rate o f Re tu rn on I nves tmen t i s t h e i n t e r e s t r a t e a t which t he p r e s e n t wo r th o f annual b e n e f i t s equa l s t h e p r e s e n t wo r th o f annual c o s t s (Wet B e n e f i t s equal t o zero o r Bene f i t / C o s t R a t i o equal t o u n i t y ) . The i n t e r n a l Rate o f Re tu rn i s 16.8%.

BREAK EVEN ENERGY VALUE:

A s i m i l a r a l t e r n a t i v e r e t u r n t y p e graph i s p resen ted h e r e based on t h e concept o f t he Break Even Energy Value. T h i s i s t he v a l u e o f energy ( m i l l s / k W h ) wh ich makes annual c o s t s e q u i v a l e n t t o t h e annua l re - tu rn . I t i s de te rm ined by d i v i d i n g t h e Average Y e a r l y Gene ra t i on (kwh) i n t o t h e T o t a l Annual Cost ( $ 1 f o r each d i s c o u n t r a t e s e l e c t e d as shown i n t h e t a b l e above. A t 22 m i l l s / kWh, t h e Rate o f R e t u r n i s iden t i c a l t o t h a t d e r i v e d above.

26

24

W, 3

2 : 22 >.

rn = - - " - 5 -- 20 I ==,

W

18

16 k'l 1 1 t600z 12 14 16 18 2 0

DISCOUNT RATE ( % ) ( I n t e r e s t R a t e )

Figure 4 continued. Reconnaissance economic feasibility example

1 2

- - 900 L PZ: 3 I- W CT

- so0 2

---

z L Z

u I1

700 0 v

- J u a Z

Refinement of A l t e r n a t i v e s

The s f g n i f i c a n t i n t e r a c t i n g f a c t o r s i n t h e formulat ion of a small hydro

pro j ec t a r e the n a t u r e of f low/head a v a i l a b i l i t p , the performance cha rac t e r -

i s t i c s of the t u r b i n e equipment, and t h e powerhouse s t r u c t u r e needed t o

accommodate the s p e c i f i c genera t ing equipment. The amount of energy that

can be generated is dependent upon the range of f low t h a t can b e passed

through the t u r b i n e and upon the head v a r i a t i o n . The range of flow t h a t

can b e u t i l i z e d i s t h e r e f o r e a func t ion of t h e i n s t a l l e d capac i ty , t ype of

t u r b i n e (operat ing range and e f f i c i e n c y c h a r a c t e r i s t i c s ) , and t h e number of

u n i t s . Each of t h e s e v a r i a b l e s a f f e c t s t h e s i z e and shape of t h e powerhouse.

A p r o j e c t formulat ion s t r a t e g y t h a t progresses through t h r e e p rog res s ive

s t a g e s of f e a t u r e s i z i n g and s e l e c t i o n i s suggested. The f i r s t s t a g e ,

e s s e n t i a l l y performance of a reconnaissance formulat ion a s d iscussed previous ly ,

y i e l d s a prelinuinary e s t i m a t e of the p r o j e c t i n s t a l l e d capac i ty . The second

s t a g e inco rpora t e s machine performance c h a r a c t e r i s t i c s i n t h e formula t ion

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

type of t u r b i n e u n i t s t h a t thus cons ider s i t e cond i t i ons and t r a d e o f f s

between u n i t performance and energy generated. The f i n a l , s t a g e concludes

the p r o j e c t formulat ion by examining t h e performance of t h e more promising

one o r more a l t e r n a t i v e s in a s e q u e n t i a l power rou t ing a n a l y s i s .

Hydrologic parameters p lay an important p a r t i n ref inement of a l t e r n a t i v e s .

I n i t i a l l y and dur ing t h e f i r s t s t a g e , and perhaps t h e second, flow-duration

techniques a r e judged t o be gene ra ly adequate. Duration cu rve a n a l y s i s

r e q u i r e s t h e u s e of a s i n g l e va lue (weighted) f o r head and a s i n g l e va lue

(average) f o r e f f i c i e n c y . Refinement occurs w i th t h e u s e of a cont inuous

record of s t ream f low and performance of s equen t i a l power rou t ings . This

procedure a s s u r e s t h a t important s equen t i a l i s s u e s of vary ing upstream and

downstream water l e v e l s , machine performance, and flow passage by t h e s i t e

are proper ly incorpora ted i n t h e a n a l y s i s . The more complete s imu la t ion

w i l l t r a c e t h e t u r b i n e performance and may r e s u l t i n s l i g h t l y h ighe r o r

lower power and energy ou tpu t e s t ima te s . The a r r a y of r e f i n e d p r o j e c t

formula t ions a r e then subjec ted t o f u l l f e a s i b i l i t y a n a l y s i s .

Economic Analysis Cost Consideration.

I:n the manual, economic and f i n a n c i a l a n a ' l y ~ i s have been c a r e f u l l y

def ined a s having d i s t i n c l y d i f f e r e n t purposes, and consequent ly, d i s t i n c t l y

d i f f e r e n t (al though v e r y much s i m i l a r ) c o s t da t a . Ec0nomi.c f e a s i b i l i t y

ana1,ysis compares economic c o s t s w i t h p r o j e c t economic b e n e f i t s wh i l e

f i n a n c i a l f e a s i b i l i t y a n a l y s i s develops t h e s p e c i f i c ca sh f low and a s s e s s e s

f inanc ing and repayment i s s u e s . The economic comparison i s p rope r ly made

us ing a common v a l u e base, (e.g., d o l l a r ava lues as of t h e s tudy y e a r ) .

Federa l government p o l i c i e s have g e n e r a l l y r e s u l t e d i n f i x i n g p r i c e l e v e l s

f o r valuing f u t u r e c o s t s and b e n e f i t s i n v a l u e terms as of the s tudy d a t e

a s w e l l and t h e t h e frame commbnly used for c o a t / b e n e f i t a n a l y s i s beg ins t h e

f i r s t y e a r of p r o j e c t ope ra t ion and extends through the p r o j e c t economic

l i f e . The a l t e r n a t i v e convention o f t e n adopted i n t h e p r i v a t e s e c t o r i s

t o state a l l p r o j e c t c o s t s and b e n e f i t s i n d o l l a r v a l u e s a s of the i n i t i a l

y e a r of ope ra t ion , S ince s m a l l hydro p r o j e c t s a r e expected t o be implemented

i n s h o r t t ime frames, the t i m e and year s ta tement of d o l l a r v a l u e s should

n o t be ~ r i t f ~ c a l .

The i n c l u s i o n of c o s t and v a l u e changes i n economic f e a s i b i l i t y

a n a l y s i s must b e handled w i t h ca re . i3 p r i n c i p l e , a p r i c e level change

economic a n a l y s i s should f o r e c a s t t h e change i n va lue f o r a l l a s p e c t s of the

f e a s i b i l i t y assessment, b o t h t h e c o s t s2de and i t s several components, and

t h e b e n e f i t s i d e Ce.g., a l t e r n a t i v e f u e l c o s t s ) and i t s several components.

The c o s t and b e n e f i t s t reams are then cons t ruc t ed from t h e s e f o r e c a s t s and

t h e f e a s i b i l i t y assessment performed. The usua l r e s u l t of i nc lud ing c o s t

and v a l u e e s c a l a t i o n i n p r o j e c t s such a s s m a l l hydro ( l a r g e i n i t i a l c o s t

followed by s m a l l 0 & My and long s t ream of p r o j e c t b e n e f i t s ) is t o make

them appear more economically a t t r a c t i v e , e.g. , b e n e f i t s grow w i t h t i m e w h i l e

c o s t s i n c r e a s e s l i g h t l y based on 0 & M. The impetus f o r inc luding v a l u e

changes i s t h e conv ic t ion t h a t b e n e f i t s wil .1 cont inue t o r i .se knowing t h a t

some b e n e f i t elements a r e i nc reas ing more rapidly than t h e gene ra l i n f l a t i o n

r a t e , e.g., f o s s i l f u e l c o s t s . The argument i s t h a t ignor ing t h e s e v a l u e

s h i f t s l e a d s t o i n c o r r e c t dec i s ions , (e.g., t h e p r o j e c t may appear i n f e a s i b l e

when it should b e found t o be f e a s i b l e ) even though t h e o r e t i c a l l y , (Eowe, 1971)

i r lc lusion of general p r i c e rise [ i n f l a t i o n , no t d i f f e r e n t i a l c o s t e s c a l a t i o n )

does no t a f f e c t t h e f e a s i b i l i t y de te rmina t ion .

The argument a g a i n s t inc luding p r i c e l e v e l change and/or gene ra l c o s t

e s c a l a t i o n i n economic f e a s i b i l i t y a n a l y s i s i s t h a t change i n p r i c e fo re -

c a s t i n g is f r augh t w i t h p i t f a l l s t h a t a r e bo th i n s t i t u t i o n a l l y and technolo-

g i c a l l y dependent. The r e s u l t i n g a n a l y s i s t hus o f t e n becomes suspec t and a

cand ida t e f o r s u b j e c t i v e manipulat ion, i . e . , a means of j u s t i f y i n g p r o j e c t s .

I f c o s t and va lue change a n a l y s i s a r e adopted f o r t h e economic a n a l y s i s ,

cons ide rab le c a r e should b e taken t o r i g o r o u s l y observe t h e b a s i c p r i n c i p l e s

and t o document t h e c r i t i c a l va lue change f o r e c a s t s .

F inanc ia l Analysis Cost Considerat i o n s

F b a n c t a l f e a s i B i l i t y a n a l y s i s develops, among o t h e r d a t a , t h e s p e c i f i c

c a s h f l o w c h a r a c t e r i s t i c s Cdollars Cn and o u t of the accounts) of the p r o j e c t .

The need i s t o f o r e c a s t the amount and t iming of c a s h ou t f low and revenue

income a s a c c u r a t e l y as poss ib l e . The cash f low a n a l y s i s is u s u a l l y cons t ruc t ed

f o r the p r o j e c t implementation per iod , t h e f i r s t year of ope ra t ion o f t e n

be ing c r i t i c a l . t o p r o j e c t ca sh reserves. To perform t h e a n a l y s i s , t h e

c o n s t r u c t i o n c o s t s are indexed t o t h e a c t u a l d a t e of c o n t r a c t award; i n t e r e s t

du r ing c o n s t r u c t i o n i s added a long w i t h r e c u r r i n g c o s t s (opera t ions and

maintenance) e s c a l a t e d based on increased c o s t s t o s e r v i c e aging equipment

and on an t ic i -pa ted general c o s t i n f l a t i o n ; and t h e revenue s t ream i s

a d j u s t e d based on a n t i c i p a t e d power s a l e c o n t r a c t p rov i s ions f o r payment

of p r o j e c t power. I f t h e r e were no c o s t i n f l a t i o n , no borrowing r equ i r ed ,

and i f p r o j e c t revenues captured a1.l. p r o j e c t b e n e f i t s exac t ly , t h e economic

c o s t and b e n e f i t streams and t h e f i n a n c i a l c o s t and revenue cash f low

streams would b e i d e n t i c a l .

TIME, COST, AND RESOURCES FOR FEASTBILTTY AND RECONNAISSANCE STUDIES

The time, c o s t s , and manpower r e sou rces r equ i r ed t o perform reconnais-

sance and f e a s i b i l i t y s t u d i e s f o r s m a l . 1 h y d r o e l e c t r i c power p l a n t a d d i t i o n s

v a r i e s depending on expected p l a n t s i z e , s i te condi t ions , s p e c i f i c scope

and depth of s tudy, and a v a i l a b i l i t y of information (bas ic d a t a and p r i o r

s t u d i e s ) . Each of t h e f i v e suppor t ing volumes i n t h e manual provides genera l

guidance on t h i s t o p i c i n t h e i r r e s p e c t i v e s u b j e c t a r e a s . The American

Soc ie ty of Civil Engineers has publ ished gene ra l gu ide l ines f o r compensation

f o r the performance of engineering s e r v i c e s (ASCE, 1972). Analysis of

t h e s e g u i d e l i n e s i n l i g h t of r e c e n t f e a s i b i l i t y s tudy experience sugges ts

t h a t f e a s i b i l i t y s tudy c o s t s , no t ing t h e f a i r l y s p e c i a l i z e d n a t u r e of

s eve ra l of t h e i s s u e s important t o smal l hydro, should range from 1.5%

t o 3% of es t imated cons t ruc t ion c o s t . Reconnaissance s t u d i e s , "mini

f e a s i b i l i t y s tud ies" , es t imated a s 10% of f e a s i b i l i t y s tudy c o s t s , would

t h e r e f o r e range from 0.15% t o 0.3% of es t imated cons t ruc t ion c o s t . A

reconnaissance s tudy f o r a 1 MW p l a n t might c o s t approximately $3,000 ( o r

about 10-15 man-days) and f o r a 1 5 MW p l a n t , perhaps $12,000 (45 t o 60 man-days).

Using 2.5% a s conse rva t ive e s t ima te f o r f e a s i b i l i t y s tudy c o s t s r e s u l t s

i n s tudy c o s t s ranging from $25,000 (80 t o 110 man-days) f o r a 1 MW p l a n t t o

$150,000 (600 t o 750 man-days) f o r t h e l a r g e r p l a n t s . The t i m e r equ i r ed t o

perform t h e f e a s i b i l i t y s tudy could range from 60 days f o r t h e s m a l l ,

r e l a t i v e l y s imple power a d d i t i o n t o upwards of 6 t o 9 months f o r l a r g e r more

complex p r o j e c t s .

The p a r t i c i p a t i n g p ro fe s s iona l s f o r a f e a s i b i l i t y s tudy inc lude c i v i l ,

e l e c t r i c a l and mechanical engineers , power economists, and e s p e c i a l l y f o r

p r i v a t e proponent p r o j e c t s , t h e s e r v i c e s of f i n a n c i a l s p e c i a l i s t s . P r o j e c t s

t h a t s i g n i f i c a n t l y al ter t h e f low regime o r phys i ca l environment w i l l l i k e l y

need t h e s e r v i c e s of water q u a l i t y and f i s h and wi ld l i f e s p e c i a l i s t s . The

p a r t i c i p a t i n g p ro fe s s iona l s f o r a reconnaissance s tudy would l i k e l y inc lude

c i v i l , mechanical, and e l e c t r i c a l engineer , and power economist f o r l a r g e r

proposed p r o j e c t s . Reconnaissance i n v e s t i g a t i o n s of smal le r p r o j e c t s may

requi re lmore v e r s i t i l i t y i n fewer p ro fe s s iona l such a s , experienced engineer

and economist.

STATUS OF MANUAL

The manual is p r e s e n t l y ( Ju ly 1979) undergoing f i n a l e d i t i n g , type-

s e t t i n g , and p r i n t i n g . P r i o r i t y d i s t r i b u t i o n is planned f o r l a t e August and

gene ra l pub l i c d i s t r i b u t i o n i n October.

ACKNOWLEDGEMENTS

The manual preparat ion was the r e s p o n s i b i l i t y of t h e Hydrologic Engineering

Center, B i l l S. Eichert , Director . The Corps I n s t i t u t e f o r Water Resources

sponsored tha manual prepara t ion a s a complementary t a sk to t h e management

of t h e National Hydropower Plan a c t i v i t i e s f o r which they a r e responsible.

The Department of Energy provided funding support under t h e i r small s c a l e

hydropower commercialization program. The preparat ion of t h e manual was

a j o i n t e f f o r t by s t a f f of t h e HEC and severa l p r i v a t e consul tants . The

principal-in-charge w a s M r . Darryl Davis of the HEC. The "Technical Guide"

volume was wr i t t en by t h e principal-in-charge aided by M r . Brian Smith, a

member of h i s s t a f f . The "Hydrologic Studies" volume was w r i t t e n by M r .

Dale Burnett of t h e HEC aided by h i s s t a f f . The remaining volumes w e r e

prepared under con t rac t t o t h e HEC a s follows: "Civil Features" and "Electro-

mechanical Features" - Tudor Engineering Co . , San Francisco, CA; "Existing

F a c i l i t i e s In tegr i ty" - W. A. FJahl.er & Assoc., Palo Alto, CA; "Economic and

Financial Analysis" - Development and Resources Corporation, Sacramento, CA.

REFERENCES

1. American S o c i e t y of C i v i l Engineers, ASCE Manuals and Reports on Engineer- ing P r a c t i c e , "No. - 45, Consul t ing Engineer ing . . . A Guide for t h e Engagement o f Engineer ing Se rv i ce s ,'I 1972.

2 . 95 th Congress, 2nd Sess ion , PT, 9.5-617, "Publ ic U t i 1 i t i . e ~ Regulatory P o l i c i e s Act," November 1978.

3 - Howe, Charles W., "Benefi t Cost Analys i s f o r Water System Planning", American Geophysical Union, Water Resources Monograph 2 , 1971.

4 . The Hydrologic Engineer ing Center (HEC), Davis, CA., 95616, F e a s i b i l i t y S t u d i e s f o r Small Hydropower Addi t ions , 6 Volumes, J u l y 1979. -

Technical Paper Series TP-1 Use of Interrelated Records to Simulate Streamflow TP-2 Optimization Techniques for Hydrologic

Engineering TP-3 Methods of Determination of Safe Yield and

Compensation Water from Storage Reservoirs TP-4 Functional Evaluation of a Water Resources System TP-5 Streamflow Synthesis for Ungaged Rivers TP-6 Simulation of Daily Streamflow TP-7 Pilot Study for Storage Requirements for Low Flow

Augmentation TP-8 Worth of Streamflow Data for Project Design - A

Pilot Study TP-9 Economic Evaluation of Reservoir System

Accomplishments TP-10 Hydrologic Simulation in Water-Yield Analysis TP-11 Survey of Programs for Water Surface Profiles TP-12 Hypothetical Flood Computation for a Stream

System TP-13 Maximum Utilization of Scarce Data in Hydrologic

Design TP-14 Techniques for Evaluating Long-Tem Reservoir

Yields TP-15 Hydrostatistics - Principles of Application TP-16 A Hydrologic Water Resource System Modeling

Techniques TP-17 Hydrologic Engineering Techniques for Regional

Water Resources Planning TP-18 Estimating Monthly Streamflows Within a Region TP-19 Suspended Sediment Discharge in Streams TP-20 Computer Determination of Flow Through Bridges TP-21 An Approach to Reservoir Temperature Analysis TP-22 A Finite Difference Methods of Analyzing Liquid

Flow in Variably Saturated Porous Media TP-23 Uses of Simulation in River Basin Planning TP-24 Hydroelectric Power Analysis in Reservoir Systems TP-25 Status of Water Resource System Analysis TP-26 System Relationships for Panama Canal Water

Supply TP-27 System Analysis of the Panama Canal Water

Supply TP-28 Digital Simulation of an Existing Water Resources

System TP-29 Computer Application in Continuing Education TP-30 Drought Severity and Water Supply Dependability TP-31 Development of System Operation Rules for an

Existing System by Simulation TP-32 Alternative Approaches to Water Resources System

Simulation TP-33 System Simulation of Integrated Use of

Hydroelectric and Thermal Power Generation TP-34 Optimizing flood Control Allocation for a

Multipurpose Reservoir TP-35 Computer Models for Rainfall-Runoff and River

Hydraulic Analysis TP-36 Evaluation of Drought Effects at Lake Atitlan TP-37 Downstream Effects of the Levee Overtopping at

Wilkes-Barre, PA, During Tropical Storm Agnes TP-38 Water Quality Evaluation of Aquatic Systems

TP-39 A Method for Analyzing Effects of Dam Failures in Design Studies

TP-40 Storm Drainage and Urban Region Flood Control Planning

TP-41 HEC-5C, A Simulation Model for System Formulation and Evaluation

TP-42 Optimal Sizing of Urban Flood Control Systems TP-43 Hydrologic and Economic Simulation of Flood

Control Aspects of Water Resources Systems TP-44 Sizing Flood Control Reservoir Systems by System

Analysis TP-45 Techniques for Real-Time Operation of Flood

Control Reservoirs in the Merrimack River Basin TP-46 Spatial Data Analysis of Nonstructural Measures TP-47 Comprehensive Flood Plain Studies Using Spatial

Data Management Techniques TP-48 Direct Runoff Hydrograph Parameters Versus

Urbanization TP-49 Experience of HEC in Disseminating Information

on Hydrological Models TP-50 Effects of Dam Removal: An Approach to

Sedimentation TP-51 Design of Flood Control Improvements by Systems

Analysis: A Case Study TP-52 Potential Use of Digital Computer Ground Water

Models TP-53 Development of Generalized Free Surface Flow

Models Using Finite Element Techniques TP-54 Adjustment of Peak Discharge Rates for

Urbanization TP-55 The Development and Servicing of Spatial Data

Management Techniques in the Corps of Engineers TP-56 Experiences of the Hydrologic Engineering Center

in Maintaining Widely Used Hydrologic and Water Resource Computer Models

TP-57 Flood Damage Assessments Using Spatial Data Management Techniques

TP-58 A Model for Evaluating Runoff-Quality in Metropolitan Master Planning

TP-59 Testing of Several Runoff Models on an Urban Watershed

TP-60 Operational Simulation of a Reservoir System with Pumped Storage

TP-61 Technical Factors in Small Hydropower Planning TP-62 Flood Hydrograph and Peak Flow Frequency

Analysis TP-63 HEC Contribution to Reservoir System Operation TP-64 Determining Peak-Discharge Frequencies in an

Urbanizing Watershed: A Case Study TP-65 Feasibility Analysis in Small Hydropower Planning TP-66 Reservoir Storage Determination by Computer

Simulation of Flood Control and Conservation Systems

TP-67 Hydrologic Land Use Classification Using LANDSAT

TP-68 Interactive Nonstructural Flood-Control Planning TP-69 Critical Water Surface by Minimum Specific

Energy Using the Parabolic Method

TP-70 Corps of Engineers Experience with Automatic Calibration of a Precipitation-Runoff Model

TP-71 Determination of Land Use from Satellite Imagery for Input to Hydrologic Models

TP-72 Application of the Finite Element Method to Vertically Stratified Hydrodynamic Flow and Water Quality

TP-73 Flood Mitigation Planning Using HEC-SAM TP-74 Hydrographs by Single Linear Reservoir Model TP-75 HEC Activities in Reservoir Analysis TP-76 Institutional Support of Water Resource Models TP-77 Investigation of Soil Conservation Service Urban

Hydrology Techniques TP-78 Potential for Increasing the Output of Existing

Hydroelectric Plants TP-79 Potential Energy and Capacity Gains from Flood

Control Storage Reallocation at Existing U.S. Hydropower Reservoirs

TP-80 Use of Non-Sequential Techniques in the Analysis of Power Potential at Storage Projects

TP-81 Data Management Systems of Water Resources Planning

TP-82 The New HEC-1 Flood Hydrograph Package TP-83 River and Reservoir Systems Water Quality

Modeling Capability TP-84 Generalized Real-Time Flood Control System

Model TP-85 Operation Policy Analysis: Sam Rayburn

Reservoir TP-86 Training the Practitioner: The Hydrologic

Engineering Center Program TP-87 Documentation Needs for Water Resources Models TP-88 Reservoir System Regulation for Water Quality

Control TP-89 A Software System to Aid in Making Real-Time

Water Control Decisions TP-90 Calibration, Verification and Application of a Two-

Dimensional Flow Model TP-91 HEC Software Development and Support TP-92 Hydrologic Engineering Center Planning Models TP-93 Flood Routing Through a Flat, Complex Flood

Plain Using a One-Dimensional Unsteady Flow Computer Program

TP-94 Dredged-Material Disposal Management Model TP-95 Infiltration and Soil Moisture Redistribution in

HEC-1 TP-96 The Hydrologic Engineering Center Experience in

Nonstructural Planning TP-97 Prediction of the Effects of a Flood Control Project

on a Meandering Stream TP-98 Evolution in Computer Programs Causes Evolution

in Training Needs: The Hydrologic Engineering Center Experience

TP-99 Reservoir System Analysis for Water Quality TP-100 Probable Maximum Flood Estimation - Eastern

United States TP-101 Use of Computer Program HEC-5 for Water Supply

Analysis TP-102 Role of Calibration in the Application of HEC-6 TP-103 Engineering and Economic Considerations in

Formulating TP-104 Modeling Water Resources Systems for Water

Quality

TP-105 Use of a Two-Dimensional Flow Model to Quantify Aquatic Habitat

TP-106 Flood-Runoff Forecasting with HEC-1F TP-107 Dredged-Material Disposal System Capacity

Expansion TP-108 Role of Small Computers in Two-Dimensional

Flow Modeling TP-109 One-Dimensional Model for Mud Flows TP-110 Subdivision Froude Number TP-111 HEC-5Q: System Water Quality Modeling TP-112 New Developments in HEC Programs for Flood

Control TP-113 Modeling and Managing Water Resource Systems

for Water Quality TP-114 Accuracy of Computer Water Surface Profiles -

Executive Summary TP-115 Application of Spatial-Data Management

Techniques in Corps Planning TP-116 The HEC's Activities in Watershed Modeling TP-117 HEC-1 and HEC-2 Applications on the

Microcomputer TP-118 Real-Time Snow Simulation Model for the

Monongahela River Basin TP-119 Multi-Purpose, Multi-Reservoir Simulation on a PC TP-120 Technology Transfer of Corps' Hydrologic Models TP-121 Development, Calibration and Application of

Runoff Forecasting Models for the Allegheny River Basin

TP-122 The Estimation of Rainfall for Flood Forecasting Using Radar and Rain Gage Data

TP-123 Developing and Managing a Comprehensive Reservoir Analysis Model

TP-124 Review of U.S. Army corps of Engineering Involvement With Alluvial Fan Flooding Problems

TP-125 An Integrated Software Package for Flood Damage Analysis

TP-126 The Value and Depreciation of Existing Facilities: The Case of Reservoirs

TP-127 Floodplain-Management Plan Enumeration TP-128 Two-Dimensional Floodplain Modeling TP-129 Status and New Capabilities of Computer Program

HEC-6: "Scour and Deposition in Rivers and Reservoirs"

TP-130 Estimating Sediment Delivery and Yield on Alluvial Fans

TP-131 Hydrologic Aspects of Flood Warning - Preparedness Programs

TP-132 Twenty-five Years of Developing, Distributing, and Supporting Hydrologic Engineering Computer Programs

TP-133 Predicting Deposition Patterns in Small Basins TP-134 Annual Extreme Lake Elevations by Total

Probability Theorem TP-135 A Muskingum-Cunge Channel Flow Routing

Method for Drainage Networks TP-136 Prescriptive Reservoir System Analysis Model -

Missouri River System Application TP-137 A Generalized Simulation Model for Reservoir

System Analysis TP-138 The HEC NexGen Software Development Project TP-139 Issues for Applications Developers TP-140 HEC-2 Water Surface Profiles Program TP-141 HEC Models for Urban Hydrologic Analysis

TP-142 Systems Analysis Applications at the Hydrologic Engineering Center

TP-143 Runoff Prediction Uncertainty for Ungauged Agricultural Watersheds

TP-144 Review of GIS Applications in Hydrologic Modeling

TP-145 Application of Rainfall-Runoff Simulation for Flood Forecasting

TP-146 Application of the HEC Prescriptive Reservoir Model in the Columbia River Systems

TP-147 HEC River Analysis System (HEC-RAS) TP-148 HEC-6: Reservoir Sediment Control Applications TP-149 The Hydrologic Modeling System (HEC-HMS):

Design and Development Issues TP-150 The HEC Hydrologic Modeling System TP-151 Bridge Hydraulic Analysis with HEC-RAS TP-152 Use of Land Surface Erosion Techniques with

Stream Channel Sediment Models

TP-153 Risk-Based Analysis for Corps Flood Project Studies - A Status Report

TP-154 Modeling Water-Resource Systems for Water Quality Management

TP-155 Runoff simulation Using Radar Rainfall Data TP-156 Status of HEC Next Generation Software

Development TP-157 Unsteady Flow Model for Forecasting Missouri and

Mississippi Rivers TP-158 Corps Water Management System (CWMS) TP-159 Some History and Hydrology of the Panama Canal TP-160 Application of Risk-Based Analysis to Planning

Reservoir and Levee Flood Damage Reduction Systems

TP-161 Corps Water Management System - Capabilities and Implementation Status