Hydrology of fish culture ponds in Gualaca, Panama

Aquacultural Engineering 7 (1988) 309-320

Hydrology of Fish Culture Ponds in Gualaca, Panama D. R. Teichert-Coddington, N. Stone & R. P. Phelps Departmentof Fisheriesand AlliedAquaculturesand AlabamaAgricultural ExperimentStation,Auburn University,AL 36849, USA (Received22 October 1987; accepted26 February 1988) ABS TRA CT During 1985, rainfall, evaporation and seepage were measured in 12 experimental fish culture ponds at the Gualaca Freshwater Aquaculture Research Station, Gualaca, Panama, to provide baseline pond hydrology data for the area and a water budget for the station. Mean monthly rainfall ranged from 0 to 27 mm day-I, while pond evaporation ranged from 1"4 to 8"4 mm day- 1. An equation was developed to predict pond evaporation from solar radiation measured by photometry. Among the 12 ponds, mean seepage ranged from 19 to 58 mm day -1 and averaged 31. Seepage accounted for 87% of water lost from the ponds. A regression equation was developed to predict the quantity of water gained by runoff into ponds during rainfall. Monthly water balances (mm day-l) for the station ranged from - 3 9 to 14 and averaged -13. Water deficits occurred during 9 of 12 months. The annual water deficit could be reduced to zero should seepage be reduced by 66%. Particular attention needs to be given to pond construction on kaolinitic soils, which although high in clay, may be very porous.

INTRODUCTION Fish pond hydrology in the tropics has received little attention with no known published reports. Boyd (1982) and Boyd and Shelton (1984) described the hydrology of ponds at Auburn, Alabama, but knowledge of pond hydrology in the United States cannot be directly applied to tropical areas because of the drastic differences in climate and soils. The tropics lie between 23.5 N and 23"5 S latitude. Although rainfall varies dramatically in quantity and pattern throughout the tropics, half the tropics, including most of Panama, is climatically defined as seasonal; a rainy season is distinct from a dry season and occupies 4.5-9.5 months 309 Aquacultural Engineering 0144-8609/88/S03.50 - © 1988 ElsevierSciencePublishers Ltd, England.Printedin Great Britain

310

D. R. Teichert-Coddington, N. Stone, R. P. Phelps

of the year (Sanchez, 1976). Daily and often intense rains characterize the rainy season, while no or little rain ( < 100 mm month- ~) falls during the dry season. While the tropics can be generally characterized, there is tremendous hydrological variation within classes. In one province (Chiriqui) of Panama, average annual rainfall over a 9-year period ranged from 203 to 704 cm at 54 measuring sites (Villarreal, 1984). The economics of the tropics are largely dependent on agriculture, which is often limited by water supply either seasonally or annually. Aquaculture requires large amounts of water compared with agriculture (Boyd, 1982). This can lead to conflicts in water use between traditional agriculture and aquaculture. Therefore, it is essential that the hydrology of tropical ponds be understood to ensure that water resources are managed efficiently.

DESCRIPTION OF STUDY SITE The Gualaca Freshwater Aquaculture Research Station is 100 m above sea level in Chiriqui Province, Panama. The station is operated by National Directorate of Aquaculture (DINACC) and Animal and Farming Research Institute (IDIAP), both of the government of Panama. The site is supplied with gravity-fed water diverted from the Chiriqui River, which drains the mountainous watershed north of the station. The waters are soft and infertile, and the alluvial soils (Inceptisols) are acidic and highly permeable (Teichert-Coddington & Phelps, in press). The 12 experimental ponds were built in 1984, and contained water 9-12 months prior to our study. The ponds were built by excavation, with 45 ° interior sides, and excavated soils added to the levees. In order to seal the ponds, the bottoms were covered with 10-15 cm of imported soil (Ultisols) containing over 30% clay. However, the imported covering soils proved to be permeable because clay particles were coated with iron and aluminum oxides resulting in a granular soil structure (Sanchez, 1976). Although maximum water depth of the ponds ranged from 1.2 to 1"4 m, water levels during the experiment were maintained at 0"9 m. Pond surface areas ranged from 818 m 2 to 1037 m 2. The experimental ponds were bordered on 4 sides by drainage ditches or other ponds, so runoff and seepage into ponds was limited to the levees (watershed) immediately surrounding the ponds. The watershed area surrounding individual ponds ranged from 25% to 46% of the water surface area. Grass coverage of levees ranged from poor to good, and was sufficient to prevent erosion and mud turbidity in ponds.

Hydrology offish culture ponds in Gualaca, Panama

311

MATERIAL AND METHODS The study period extended from January to November 1985, with the exception of June, and included both dry and rainy seasons. The ponds were limed with agricultural limestone, stocked with Tilapia nilotica and fertilized with triple superphosphate (Teichert-Coddington & Phelps, in press). Water was added only to replace that lost to evaporation and seepage. Water depth (mm) was measured with a staff gauge located in each pond. Evaporation was measured in a Class A evaporation pan, utilizing a hook gauge. The pan was filled with pond water. Pan evaporation was converted to pond evaporation by multiplication with the pan factor 0.83, a mean of coefficients derived during the summer months at Auburn, Alabama (Boyd, 1985a). Actual pond evaporation may be higher due to evapo-transpiration occurring along the capillary fringe of the pond. However, 0-83 is similar to the pan factor of 0-86 used for irrigated rice fields (Yoshida, 1981 ). Rainfall was measured with a standard 10 : 1 rain gauge. All measurements were taken at least 5 times per week. Solar radiation was measured daily wtih a LiCor 1776 Solar Monitor utilizing a quantum sensor.

RESULTS Mean annual water depths for all ponds ranged from 0.82 to 1.06 m (Table 1 ). Mean monthly depths during the dry season ranged from 0.66 to 0.87 m, but rose to between 1.00 and 1.26 m during the rainy season. Mean weekly rainfall (mm day-l) ranged from 0 (January to March) to 40 (September) (Fig. 1). Monthly rainfall during the study was not abnormal in comparison to rainfalls averaged over a 4-year period at an IDIAP facility in Gualaca (Table 2). Mean weekly pond evaporation (mm day-~) ranged from 1.2 during the rainy season to 10-6 during the dry season, with an annual mean of 4.0 (Fig. 2). Evaporation rates are similar to those reported for irrigated rice fields in Asia which ranged from 1 to 6.2 mm day-1 (Yoshida, 1981 ). Higher evaporation rates during the dry season were influenced by low humidity (low rainfall) (Fig. 1), high solar radiation (Fig. 3) and stronger winds (Fig. 4). There was a strong correlation between solar radiation and pond evaporation. Weekly or monthly means of solar radiation may be used to predict mean weekly or mean monthly pond evaporation for most pond water management purposes. Regression equations where y~--weekly

D. R. Teichert-Coddington, N. Stone, R. P. Phelps

312

TABLE 1 Pond Water Surface Area and Respective Watershed Areas when Water Depth is 0"9 m (mean annual depths of ponds are also shown)

Pond

Surface area (m e)

Watershed area (m 2)

Mean water depth (m)

1 2 3 4 5 6 7 8 9 10 17 18 Mean

832 818 815 885 928 859 826 826 890 839 1037 865 868

585 591 652 532 638 581 625 583 745 273 572 701 590

0"88 0"84 0"82 0"85 0"84 1"00 1'01 0'93 1"06 1"02 0"97 0"87 0-92

45~ a

._1 .-I

,< LL

z <¢ iz

35302s201510" 5C" °

"5

IIIIIIIIIIIIIIIIIIIIII

JAN

Fig. 1.

IIIIIII

II

I IIII

IIIIII

I

FEB MAR APR MAY JUN JUL AUGSEP OCT NOV

Mean weekly rainfall during 1985 at the Gualaca Freshwater Aquaculture Research Station, Panama.

pond evaporation (mm day-l), y2=monthly pond evaporation (mm d a y - 1), Xl = w e e k l y s o l a r r a d i a t i o n ( E i n s t e i n s m - 2 d a y - 1), a n d x2 = m o n t h l y s o l a r r a d i a t i o n ( E i n s t e i n s m - 2 d a y - ~) are: Yl = 12-14 - 0.727x~ + 0.13x~ (R 2 = 0-94; P = 0 - 0 0 0 1 ; n = 36) (Fig. 5) Y2 = 0"304x2 - 7.31 ( R 2 = 0-95; P = 0 . 0 0 0 1 ; n = 10)

Hydrology offish culture ponds in Gualaca, Panama

313

TABLE 2

Average Annual Monthly Rainfall (mm day-1) over 4 years (1981-1984), and Monthly Rainfall During 1985 at the Gualaca Freshwater Aquaculture Research Station

Month

Rainfall (1981-1984)"

January February March April May June July Augu st September October November December

Rainfall

Mean

SD

1985

2 1 4 8 16 18 13 16 23 23 14 3

2-5 0"9 3-5 2.8 7"4 6"4 3-6 9"4 7-4 5 9"6 3"5

0 0 0 4 14 -9 12 27 13 14 --

SD = standard deviation "Data recorded at IDIAP, Gualaca.

a

z

O I--< fl: O Q. < > UJ

642-

0-

Fig. 2.

JAN FEB MAR APR MAY JUN JOEAUG SEP OCT NOV Mean weekly pond evaporation (pan evaporation × 0"83) during 1985 at the Gualaca Freshwater Aquaculture Research Station, Panama.

Water

budget

A monthly water budget for the station was composed using the following h y d r o l o g i c b a l a n c e e q u a t i o n : Rainfall + Runoff + Water Input = Evaporation + Seepage + Overflow

D. R. Teichert-Coddington, N. Stone, R. P. Phelps

314

5045-

"0

40353O-

2520

I

II

II

II

I|

II

II

II

II

II

II

II

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Fig. 3.

Mean weekly solar radiation (Einsteins m -2 day-l), during 1985 at the Gualaca Freshwater Aquaculture Research Station, Panama.

16n-r"

14-

,,¢,

12-

t~ w w n

10-

0 Z

8, 6'

20'

I11

I

,

JAN FEB MAR

Fig. 4.

. APR

I I I I I I I l l l l l l i l l l l MAY

JULAUGSEP

OCTNOVDEC

Mean weekly wind speeds during 1986 at the Gualaca Freshwater Aquaculture Research Station, Panama.

Water input and overflow were not measured directly, but a positive balance inferred that water was stored and/or lost to overflow, and a negative balanced inferred the quantity of river water added to compensate the loss. Seepage rates, in the absence of rainfall, can be calculated by subtracting evaporation from total pond water loss; during rainfall, however, an unmeasured quantity of water enters the ponds as runoff. Since the watershed area surrounding ponds in the present study was relatively large (Table 1), runoff during rainfall added significant water to the ponds. Current methods for estimating runoff (SCS, 1982) are crude for use with small watersheds and with rainfalls less than 25 mm. In the present study, runoff and seepage were estimated for each pond during the rainy season by regression analysis of apparent seepage [Total Water

Hydrology offish culture ponds in Gualaca, Panama

11"

y=12.14-.727x+.013x2 R2=0'94

10.

9! z 0 r,< nO ~c > ILl

315

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8"

7" 6"

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7

5" 4.

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o

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30

35

40

45

50

,

,

55

SOLARRADIATION Fig. 5. Relationship between pond evaporation (mm day -~) and solar radiation (Einsteins m -2 day-~) during 1985, at the Gualaca Freshwater Aquaculture Research Station, Panama.

Loss - (Evaporation + Rainfall)] and rainfall. The slope of the regression equation estimated the reduction in apparent seepage due to unmeasured runoff water entering the pond with a rainfall. Seepage was estimated from the equation (y intercept) when rainfall was set equal to zero. Monthly means of rainfall and apparent seepage were used in the regression equation; daily and weekly means proved to be too variable for adequate prediction purposes. The regression equation for each pond is presented in Table 3, and Fig. 6 illustrates the form of the curve resulting from these equations. All but one of the equations were second order polynomials, because as monthly rainfall increased, mean monthly pond depth increased (Fig. 7), reducing the effective watershed area of each pond. As the watershed area decreased, less runoff water per unit rainfall entered the ponds. These regression equations are site specific, but similar empirical relationships can be constructed for any aquaculture site. Pond seepage rates, ranging from 19 to 58 mm day-~ and averaging 31 for all ponds, were high. Boyd (1985b) found that seepage rates of ponds in the United States ranged from 1 to 25 mm day-1; ponds in the catfish culture areas of Alabama seeped 2 to 5 mm day-1. Reported seepage from irrigated rice fields in Asia ranged from 0.2 to 15.6 mm day - 1 (Yoshida 1981 ). In Thailand, fish ponds seeped 4 to 16 mm day - 1

316

D. R. Teichert-Coddington, N. Stone, R. P. Phelps TABLE 3

Equations, Coefficients of Determination (R2), and Associated P-values, and Number of Observations (n) for Regression of Mean Monthly Apparent Seepage (mm day-~), on Mean Monthly Rainfall (mm day -~) for Fish Culture Ponds at Gualaca, Panama (y = apparent seepage; x = rainfall) Pond 1

2 3 4 5 6 7 8 9 10 17 18 Allponds

Equation

y= 25.6 y = 43.4 y = 28.5 y= 20.7 y = 24.8 y = 19.2 y= 19"2 y = 35"1 y = 22"1 y = 30"9 y= 44"7 y = 57-7 y= 31"0 -

1.96x + 0.06 lx 2 4.27x + 0-125x 2 2.09x + 0"057X 2 1.29x + 0-033x 2 1.64x + 0-039x 2 1.24x + O'030X 2 l'12x + 0"024x2 2"40x + 0"058x2 0"92x 2"38x + 0"052x2 3"29x + 0"07lx 2 4"49x + 0"018x2 2'27x + 0"056x2

R2

P

N

0-93 0.92 0.92 0-84 0.91 0-91 0"83 0"91 0"87 0"91 0"92 0"94 0"57

0.002 0.002 0.002 0.01 0.002 0"003 0"012 0"002 0"001 0"003 0"002 0"001 0"0001

8 8 8 8 8 8 8 8 8 8 8 8 96

(Diana et al., 1985). C o m b i n e d e v a p o r a t i o n a n d seepage f r o m fish p o n d s in H o n d u r a s ranged f r o m 7 to 13 m m d a y -1 (Green et aL, 1984). T h e soils at G u a l a c a are highly permeable, but the variation a m o n g p o n d s suggests that the quality of p o n d c o n s t r u c t i o n influenced seepage rates too. R u n o f f a n d seepage in the m o n t h l y station water budget (Table 4) were m e a n s for the 12 ponds. T h e m o n t h l y hydrologic balance varied b e t w e e n a water deficit of 39 m m d a y -1 in F e b r u a r y and M a r c h to a water excess of 14 m m d a y - 1 in September. A n excess of water was r e c o r d e d for only 3 months. T h e water requirements for two 6 - m o n t h fish crops at G u a l a c a is 1 4 5 7 5 0 m 3 ha -1. Rainfall and r u n o f f w o u l d supply a p o r t i o n of the requirements (Table 4), leaving a d e m a n d of 95 050 m 3 h a - 1 , or a total of 3 0 4 1 6 0 m 3 y e a r - 1 of additional water necessary to operate the 3.2-ha research station. By comparison, a 1-ha catfish p o n d built of heavy clay soil in the Mississippi Delta region, U S A , w o u l d require an additional 21 375 m 3 y e a r - 1 of water in excess of that p r o v i d e d by rainfall, assuming the p o n d is filled a n d d r a i n e d once a year (Boyd, 1985 b ). Based o n data presented by B o y d (1982, 1985b), the small p o n d experimental area of the Fisheries R e s e a r c h Unit of A u b u m University requires 33 285 m 3 h a y e a r - 1 in a d d i t i o n to that p r o v i d e d by rainfall for a twice-a-year filling

Hydrology offish culture ponds in Gualaca, Panama

317

y=31.023-2.27x.056x2

70"

R2=.57 n =96

6050,

0

40. uJ ¢3
~

30. 20, 10,

0

!

-5

0

0~00 0

I

I

5

10

0

I

'

I

15

RAINFALL

'

20

I

I

25

30

(MM/D)

Fig. 6. Regression of mean monthly apparent seepage (total water loss-evaporation + rainfall) of 12 fish culture ponds on mean monthly rainfall during 1985, at the Gualaca Freshwater Aquaculture Research Station, Panama.

o 1.

0

O0 0 4~)0

1.1"

0 T I--0,.. ILl a

dP 0

~

1-

0

0

0 0 0 0 O ~

0

o

0o

0 o

o .9-

3° ,8 °

-5

o

o

o

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T 0

!

° I

5

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I

I

!

I

10

15

20

25

RAINFALL

1

i

30

(MM/D)

Fig. 7.

Relationship between mean monthly water depths of 12 fish culture ponds and mean monthly rainfall at the Gualaca Freshwater Aquaculture Research Station, Panama.

and draining. Irrigated rice farming in Asia, a water intensive agriculture, requires 2 4 8 0 0 m 3 ha -~ of water for two crops a year (Yoshida, 1981). Irrigation in the Southeastern U S A usually requires 3000 to 4500 m s ha - 1 y e a r - 1 (Schwab et al., 1971).

0 0 0 4 13 11 9 12 27 13 14 7 9

January February March April May June a July August September October November December ~ Mean

0 0 0 8 20 18 16 19 20 20 21 13 13

Runoff 0 0 0 12 33 29 25 31 47 33 35 20 22

Total

Watergain (mm day- 9

31 31 31 31 31 31 31 31 31 31 31 31 31

Seepage

6.2 7-8 8.4 5"6 3.1 2.3 1"4 1"6 1-8 2.4 2.6 4-4 4-0

Evap. 37 39 39 37 34 33 32 33 33 33 34 35 35

Total

Water loss (mm ay- 9

"Values estimated by interpolation since measurements were unavailable bBased on a total water surface area of 3.2 ha 'Hypothetical water balance if seepage rates were reduced from 31 to 10 mm day - 1.

Rainfall

Month

37 39 39 25 - 1 - 4 - 7 - 2 14 0 1 - 15 - 13

-

Water balance (mm day- 9 1 180 1 250 1 250 800 30 130 220 60 0 0 0 480 450

Station replacement waterb (m s day- i)

TABLE 4 Water Budget for the Gualaca Freshwater Aquaculture Research Station, during January through December, 1985

-16 -18 -18 -4 20 17 14 19 35 21 22 6 8

Potential water balance' (mm day- 1)

Hydrology offish culture ponds in Gualaca, Panama

319

Aquaculture is a water intensive crop production system, but the seepage rates resulting from the soil characteristics, and construction procedures used at the Gualaca station make it even more so. The annual water deficit at Gualaca could be decreased to 0 if seepage were decreased by 66% to 10 mm day -t, a value more representative of ponds constructed on other soil types. Current studies of Gualaca (unpublished data) indicate that high applications of chicken litter will reduce seepage. Also, observational data at Gualaca suggest that applications of low quantities of bentonite followed by a stocking of common carp to mix the bottom soils will decrease seepage rates. Much research on reducing seepage economically in tropical fish ponds needs to done. Particular attention needs to be given to pond construction on tropical kaolinitic soils which, although high in clay, may also be very porous. Water loss from ponds via seepage is a major concern in many tropical countries where despite high annual rainfalls, the rainfall is concentrated in a few months of the year. To reduce water deficits, it is imperative that fish ponds be built to conserve water by minimizing seepage. Ponds should be located with care, and core trenching of dikes and proper compaction of dikes and pond bottom soils should be standard practice (Lawrence, 1949; SCS, 1982), despite increases in construction cost. Special engineering properties of tropical soils need to be considered in the construction of ponds and their use for aquaculture.

ACKNOWLEDGMENTS We thank Medardo Peralta and the staff of Gualaca Freshwater Aquaculture Research Station for their assistance, and Richard Pretto Malca, Director of Direccion Nacional de Acuicultura, Panama, for his support of the study. This study was funded by the Pond Dynamics/Aquaculture Cooperative Research and Support Program, Title 12, USAID and the Government of Panama. CRSP Publication No. 87-18.

REFERENCES Boyd, C. E. (1982). Hydrology of small experimental fish ponds at Auburn, Alabama. Trans. Am. Fish. Soc., 111,638-44. Boyd, C. E. (1985a). Pond evaporation. Trans. Am. Fish. Soc., 114, 99-303. Boyd, C. E. (1985b). Hydrology and pond construction, In Channel Catfish Culture C. S. Tucker (ed.), Elsevier Science Publishers B. V., Amsterdam. Boyd, C. E. & Shelton, J. L., Jr. (1984). Observations on the hydrology and morphometry of ponds on the Auburn University Fisheries Research Unit.

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D. R. Teichert-Coddington, N. Stone, R. P. Phelps

Bulletin 558. Alabama Agricultural Experiment Station, Auburn University, Alabama, USA. Schwab, G. O., Frevert, A. K., Barnes, K. K. & Edminster, T. W. (1971). Elementary soil and water engineering. John Wiley and Sons, New York, USA. Soil Conservation Service (1982). Ponds-planning, design, construction. Agricultural Handbook No. 590. United States Department of Agriculture, USA. Diana, J. S., Kwei Lin, C., Schneeberger, P., Bhukaswan, T. & Sirsuwanatach, V. (1985). Progress report -- CRSP pond dynamics, Thailand. Second cycle-dry season. Great Lakes and Marine Waters Center, University of Michigan, Ann Arbor, Michigan, USA. Green, B., Alvarenga, H., Phelps, R. P. & Espinoza, J. (1984). Technical report Honduras aquaculture CRSP. Cycle 1, dry season phase. Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, Alabama, USA. Lawrence, J. M. (1949). Construction of farm fish ponds. Circular No. 95. Alabama Agricultural Experiment Station, Auburn University, Alabama, USA. Sanchez, P. A. (1976). Properties and management of soils in the tropics. John Wiley and Sons, New York, USA. Teichert-Coddington, D. R. & Phelps, R. P. (in press). Effects of seepage on water quality and productivity of inorganically fertilized tropical ponds. Journal of Tropical Aquaculture. Villarreal, C. M. (1984). Balances hidricos del suelo para la provincia de Chiriqui. Ministerio de Desarrollo Agropecuario, Panama, Republic of Panama. Yoshida, S. (1981). Fundamentals of rice crop science. International Rice Research Institute, Los Banos, Philippines. -

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