Climate Change and Disaster-Resilient Water Resources Sector Project (RRP KGZ 51081-001)

PRAVAYA VETKA IRRIGATION SYSTEM: WATER BALANCE AND DROUGHT RISK MANAGEMENT

Table of Contents I. Present Water Balances ..................................................................................................... 3

A. Stationary Climate Data .................................................................................................. 3

B. Frequency Estimates ...................................................................................................... 5

C. Without Project Water Balances ..................................................................................... 6

D. With Project Water Balance ...........................................................................................11

II. Drought Risk Assessment ..................................................................................................14

III. Climate Risk Assessment ..................................................................................................15

A. Projections and Hazard .................................................................................................15

B. Vulnerability Assessment...............................................................................................15

C. Adaptation Assessment .................................................................................................15

IV. Project Interventions ..........................................................................................................15

A. Advance Actions ............................................................................................................16

B. Normal System Operation .............................................................................................16

C. Drought Risk Management ............................................................................................16

D. Climate Change Adaptation ...........................................................................................18

Tables Table 1: Relevant historical climate record ................................................................................. 3

Table 2: Present PVIS stationary climate frequency estimates ................................................... 5

Table 3: Present PVIS compound water balance climate hazard variables ................................ 6

Table 4: Present PVIS without project water balance and cropping pattern ................................ 7

Table 5: Present PVIS without project water balance and cropping pattern ................................ 8

Table 6: Present PVIS with project water balance and cropping pattern ...................................11

Table 7: Irrigated water balance, cropping pattern and drought risk assessment ......................14

Table 8: RCP 8.5 projections of 2050 compound water balance climate hazard variables .......15

Figures Figure 1: Hydromet station locations and Vetka irrigation area (shaded) .................................... 4

Figure 2: Kara Ungur Sai River catchment areas ....................................................................... 4

Figure 3: Actual evapotranspiration and wheat yield .................................................................. 9

Figure 4: Grain yield and water productivity ..............................................................................10

Table 9: 2050 PVIS with project water balance and cropping pattern ........................................17

Table 10: Indicative water allocation and rotation plan ..............................................................18

Annex A: PVIS Representative Precipitation Data for Jalalabad Station....................................19

Annex B: PVIS Representative Streamflow Data for Tentek Sai Station ...................................21

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I. Present Water Balances 1. Irrigation systems are designed for the nominal 80% reliable water balance based on:

i. Mean potential evapotranspiration (ET0), for a standard grass reference crop, which is a function of climate (temperature, humidity, wind and radiation or sunshine) only;

ii. 80% reliable precipitation, conventionally treated as negative irrigation demand, and; iii. 80% reliable streamflow, which is a function of: (a) the sum of snow melt, glacier melt

and catchment rainfall minus (b) actual evapotranspiration (ETa). 2. The above combination represents the compound water balance climate hazard of interest. The associated irrigated cropping pattern is vulnerable to drought and climate change.

A. Stationary Climate Data

3. Three irrigation systems are supplied by Vetka Weir (improved by the World Bank):

i. Pravaya Vetka Irrigation System (PVIS), including the core subproject Nooken secondary canal, is located on the right bank of Kara Ungur Sai River.

ii. Levaya Vetka main canal in on the left bank of the Kara Ungur Sai River. It supplies: a. Levaya Vetka Irrigation System (improved by the World Bank), and its: b. Jany-Jogorku Akman secondary canal (proposed as a non-core subproject).

4. The relevant historical climate record is summarized in Table 1. Monthly data are in the annexes. Relevant station locations are in Figure 1. At both Vetka Weir (PVIS intake) and Tentek Sai gauging station locations, Kara Ungur Sai River catchment areas are shown in Figure 2.

Table 1: Relevant historical climate record

Type ID Station X Y Z Years

Hydropost 37 Tentek Sai 73.00 41.25 990 1925-1966, 1998-2003, 2010, 2016

Meteopost 35 Ak Terek 72.82 41.27 1,748 1947-2017

Meteopost 28 Jalalabad 73.00 40.95 763 1947 -2017

Source: KyrgyzHydromet

1. Potential Evapotranspiration

5. Mean monthly potential reference crop (grass) evapotranspiration (ET0) is in Table 2.

2. Rainfall 6. Jalalabad Station (Annex A, altitude 763 m) has lower mean annual rainfall (MAR) (511 mm) than Ak Terek Station (1,748 m and 1,068 mm). PVIS is located downstream of Vetka Weir (altitude 820 m). Therefore, Jalalabad Station is adequately representative of PVIS. Rainfall is:

i. Monomodal and highly seasonal: Most MAR falls in the Dec to Feb spring (39%) with only 9% falling in the Jun to Aug summer. Therefore, an early late-winter start, to the single spring cropping season, is required to avoid summer water shortages;

ii. Mean annual rainfall (511 mm) is only 45% of potential evapotranspiration (1,124 mm).

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Therefore, catchment runoff (rainfall minus actual ET ) is unlikely to contribute much and upper-catchment snow and glacier melt is the main source of streamflow;

iii. Variable and unreliable: MAR is 511 mm and 50% reliable annual rainfall is 497 mm but the annual sum of 50% reliable monthly streamflow is only 379 mm (74% of MAR).

Figure 1: Hydromet station locations and Vetka irrigation area (shaded)

Figure 2: Kara Ungur Sai River catchment areas

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3. Streamflow 7. Tentek Sai Station (1,272 km2 area and 2,220 m average altitude) has mean annual flow (MAF) of 29.3 m3 sec-1 (Annex B). This is equivalent to 726 mm over its 1,272 km2 catchment. Orographic effects are evident in the Jalalabad and Ak Terek station rainfall records. These indicate that MAR = - 3,948.7 + 671.92 x ln(Altitude), catchment rainfall is about 1,229 mm and rainfall (1,229 mm) minus actual ET (potential ET = 1,124 mm) is unlikely to contribute much to MAF (726 mm). This confirms that snow and glacier melt are the main sources of streamflow. DWR advises that:

i. Kara Ungur Sai River is mainly fed by snow melt, rather than glacier melt; ii. At Vetka Weir (VW), annual Kara Ungur Sai streamflow is 750 MCM to 850 MCM. At

Tentek Sai (TS) Station, MAF and the annual sum of 50% reliable monthly streamflow (Table 2) are 29.3 cumec and 26.4 cumec, or 924 MCM and 834 MCM respectively. Therefore, TS is sufficiently representative of Kara Ungur Sai River streamflow at VW.

iii. From 2012 to 2017 inclusive, annual VW diversions were 55.1 MCM and 37.0 MCM to the Pravaya Vetka and Levaya Vetka main canals respectively. Therefore, about 60% of Tentek Sai Station streamflow is available for diversion to PVIS at Vetka Weir;

B. Frequency Estimates

Table 2: Present PVIS stationary climate frequency estimates

Var R (%) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Q

50 5.6 5.7 10.1 30.3 43.1 35.9 19.8 11.3 7.6 7.0 7.2 6.3

80 4.3 4.3 7.4 17.6 24.0 24.8 13.6 8.0 5.7 5.4 5.2 4.8

90 3.7 3.7 6.3 13.3 17.7 20.4 11.2 6.7 4.9 4.7 4.4 4.2

95 3.3 3.3 5.5 10.5 13.8 17.4 9.5 5.8 4.4 4.2 3.8 3.7

99 2.6 2.6 4.3 6.8 8.6 12.9 7.0 4.4 3.5 3.3 2.9 2.9

99.9 2.1 2.0 3.2 4.1 5.0 9.2 5.0 3.2 2.7 2.6 2.1 2.3

99.99 1.7 1.6 2.5 2.8 3.3 7.0 3.8 2.5 2.2 2.1 1.7 1.9

ET0 50 20 24 48 91 137 175 193 174 127 76 37 22

P

50 39.1 49.4 63.9 62.8 43.0 17.1 4.3 0.8 2.8 15.9 41.1 38.3

80 22.6 30.8 36.8 39.2 23.6 5.2 0.7 0.1 0.4 2.0 19.4 19.4

90 17.0 24.1 27.6 30.6 17.2 2.8 0.3 0.0 0.0 0.7 13.1 13.6

95 13.4 19.7 21.8 25.0 13.3 1.7 0.0 0.0 0.0 0.3 9.5 10.2

99 8.6 13.4 13.9 17.1 8.2 0.6 0.0 0.0 0.0 0.0 5.2 5.9

99.9 5.3 8.7 8.5 11.1 4.7 0.2 0.0 0.0 0.0 0.0 2.6 3.2

99.99 3.5 6.1 5.6 7.8 3.0 0.1 0.0 0.0 0.0 0.0 1.5 1.9 Legend: ET0 = potential evapotranspiration (mm), P = precipitation (mm), Q = discharge (m3 sec-1), R = reliability.

Sources: ET0 = CROPWAT 1 Penman-Monteith estimates, based on FAO CLIMWAT 2 data for representative Uzgen station, P = Annex A, Q = 60% of Annex B and R = TRTA log-normal distribution frequency estimates.

1 FAO. 2006. Crop Evapotranspiration: Guidelines for Computing Crop Water Requirements: FAO I&D Paper 56. 2 http://www.fao.org/land-water/databases-and-software/climwat-for-cropwat/en/.

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C. Without Project Water Balances

1. Compound Climate Hazard

Table 3: Present PVIS compound water balance climate hazard variables

Var Unit Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Q80 m3 s-1 4.3 4.3 7.4 17.6 24.0 24.8 13.6 8.0 5.7 5.4 5.2 4.8

Q* m3 s-1 4.3 4.3 7.4 17.6 18.0 18.0 13.6 8.0 5.7 5.4 5.2 4.8

Q* MCM 11.5 10.5 19.8 45.6 48.2 46.7 36.4 21.4 14.8 14.5 13.5 12.9

ET0 MCM 2.7 3.2 6.5 12.3 18.5 23.6 26.1 23.5 17.1 10.3 5.0 3.0

P80 MCM 3.1 4.2 5.0 5.3 3.2 0.7 0.1 0.0 0.1 0.3 2.6 2.6

WB80 MCM 11.9 11.5 18.3 38.6 32.9 23.8 10.4 -2.1 -2.2 4.5 11.1 12.5

Legend: ET0 = potential (reference crop) evapotranspiration, P80 = 80% reliable precipitation, PVIS = Pravaya Vetka Irrigation System, serving an area of 13,500 ha, Q80 = 80% reliable streamflow or discharge, Q* = Q80 adjusted for main canal design delivery capacity (18.0 cumec) and WB80 = the 80% reliable water balance = (Q* + P80 – ET0).

2. Present Cropping Pattern

8. Mean monthly minimum temperatures are – 4.3 oC (March), + 3.0 oC (April), + 0.4 oC (October) and – 5.3 oC (November). Therefore, as rainfall is minimal, Table 2 indicates that there is effectively a single seven month irrigated cropping season from April to October inclusive of the water deficits in late summer (August) and early autumn (September). 9. In estimating actual (Pa) and potential (Pc) productivities of water (PoW) consumed, the dilemma is that: (i) Ya is usually measured and known but ETa is not, unless satellite images have been interpreted (SII) to estimate ETa and (ii) ETc can be estimated using standard procedures.3 However, available CropWat and AquaCrop4 models for estimating Yc are not widely employed. Therefore, SII of PoW consumed and application of these models is included as an advance action for the project’s phased implementation. The conventional approach is to assume that crop water requirements (CWR) are fully met. 10. The present cropping calendar is in Table 4 together with the associated water balance assuming that potential crop water requirements (CWR or ETc) are fully met. This confirms that August is the critical month when irrigation system efficiency (ISE) would need to be 87% to fully meet CWR. However, this 87% is implausible as, in this context, ISE includes: (i) diversion efficiency (river discharge / diversion) as well as conventional (ii) main system delivery efficiency (primary to quaternary canals) and (iii) farmer field-level application efficiency. 11. Furthermore, the annual sum of monthly diversions, required to fully meet CWR (ETc), is 103.1 MCM whereas DWR advise that, from 2012 to 2017 inclusive, annual Vetka Weir diversions were only 55.1 MCM (PIC to verify this during implementation). This implies an impossible ISE of 103.1 / 55.1 = 187%. Alternatively, this implies actual crop evapotranspiration (ETa) is: (i) a maximum of 55.1 / 103.1 = 53% of ETc, if an unrealistic ISE of 100% can be attained, or (ii) only

3 FAO. 2006. Crop Evapotranspiration – Guidelines for Computing Crop Water Requirements – I & D paper 56. 4 FAO. 2012. Crop Yield Response to Water - Irrigation and drainage paper 66, http://www.fao.org/docrep/016/i2800e/i2800e00.htm.

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40% of ETc, if a challenging ISE of 75% can be attained and (iii) so on. ETa is assessed below.

Table 4: Present PVIS without project water balance and cropping pattern assuming actual crop evapotranspiration (ETa) = potential crop evapotranspiration (ETc)

Var % Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Lucerne 14

Cotton 36

Corn 17

Wheat 18

Veg 10

Fruit 5

ET0 MCM 2.7 3.2 6.5 12.3 18.5 23.6 26.1 23.5 17.1 10.3 5.0 3.0

Lucerne Kc 0.40 0.40 0.40 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.40 0.40

Cotton Kc 0.35 0.64 1.13 1.20 1.15 0.80

Corn Kc 0.30 0.75 1.18 1.20 0.75

Wheat Kc 0.40 0.40 0.40 0.80 1.15 1.00 0.40 0.40 0.40

Veg 5 Kc 0.75 1.10 1.05 0.75 1.10 1.05

Fruit Kc 0.20 0.20 0.20 0.45 0.45 0.60 0.90 0.95 0.70 0.70 0.20 0.20

Lucerne 100 1.1 1.3 2.6 11.7 17.6 22.4 24.8 22.3 16.2 9.8 2.0 1.2

Cotton 100 0 0 0 4.3 11.8 26.7 31.3 27.0 13.7 0 0 0

Corn 100 0 0 0 3.7 13.9 27.8 31.3 17.6 0 0 0 0

Wheat 100 1.1 1.3 2.6 9.8 21.3 23.6 0 0 0 4.1 2.0 1.2

Veg 100 0 0 0 9.2 20.4 24.8 0 17.6 18.8 10.8 0 0

Fruit 100 0.5 0.6 1.3 5.5 8.3 14.2 23.5 22.3 12.0 7.2 1.0 0.6

Lucerne 14 0.2 0.2 0.4 1.6 2.5 3.1 3.5 3.1 2.3 1.4 0.3 0.2

Cotton 36 0 0 0 1.5 4.3 9.6 11.3 9.7 4.9 0 0 0

Corn 17 0 0 0 0.6 2.4 4.7 5.3 3.0 0 0 0 0

Wheat 18 0.2 0.2 0.5 1.8 3.8 4.2 0 0 0 0.7 0.4 0.2

Veg 10 0 0 0 0.9 2.0 2.5 0 1.8 1.9 1.1 0 0

Fruit 5 0 0 0.1 0.3 0.4 0.7 1.2 1.1 0.6 0.4 0.1 0

Sum ETc 0.4 0.4 1.0 6.7 15.4 24.8 21.3 18.7 9.7 3.6 0.8 0.4

Rain MCM 3.1 4.2 5.0 5.3 3.2 0.7 0.1 0 0.1 0.3 2.6 2.6

CI % 37 37 37 100 100 100 72 82 65 47 37 37

Eff Rain MCM 0.4 0.4 1.0 5.3 3.2 0.7 0.1 0 0.1 0.1 0.3 0.1

IWRc MCM 0 0 0 1.4 12.2 24.1 21.2 18.7 9.6 3.5 0.5 0.3

Q* MCM 11.5 10.5 19.8 45.6 48.2 46.7 36.4 21.4 14.8 14.5 13.5 12.9

ISE % 0 0 0 3 25 52 58 87 65 24 4 2

Legend: CI = cropping intensity, eg lucerne = 14%, ET0 = potential (reference crop) evapotranspiration, ETc = potential crop evapotranspiration (first for CI = 100% and then weighted for actual CI), IWRc = crop irrigation water requirement = ETc – effective rainfall, Kc = crop coefficient, MCM = million cubic meters, PVIS = Pravaya Vetka Irrigation System, serving an area of 13,500 ha, and Q* = water withdrawal or diversion.

5 For representative small vegetable crops, such as onion, as well as cucumber and beets etc.

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3. Actual Crop Evapotranspiration

12. The Comprehensive Assessment of Water Management in Agriculture (CAWMA) 6 (Figures 3 and 4) provides a basis for estimating: (i) maximum Ya and minimum ETa for wheat (Figure 3), and (ii) average Ya and ETa for corn, wheat and rice (Figure 4). In 2017, actual PVIS winter wheat yield (Ya) was 4.0 T ha-1 and CAWMA indicates minimum ETa = 240 mm and Pa = 4,000 / 2,400 = 1.67 kg m-3 and average ETa = 320 mm and Pa = 4,000 / 3,200 = 1.25 kg m-3. However, Table 4 indicates that seasonal potential crop evapotranspiration (ETc) is 67.0 MCM. This is equal to 496 mm over the 13,500 ha PVIS service area. Therefore:

i. Minimum ETa (240 mm) is only 48% of ETc, and: ii. Average ETa (320 mm) is only 65% of ETc (496 mm).

13. Similarly, in 2017, actual Pravaya Vetka corn yield was 7.0 T ha-1 of ears (grain and cob). While there is considerable variation, on average, this is equivalent to Ya = 2.8 T ha-1 of grain. 7 Figure 4 indicates that Pa = 1.0 kg m-3. Therefore, ETa = 280 mm. Table 4 indicates that seasonal ETc is 94.3 MCM or 699 mm. Therefore, average ETa (280 mm) is only 40% of ETc (699 mm). This indicates that corn is not “drinking” enough (ETa << ETc) and confirms PVIS is very short of water.

Table 5: Present PVIS without project water balance and cropping pattern based on actual crop evapotranspiration (ETa) estimated herein (Section 1.3.3)

Var % Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Lucerne 14

Cotton 36

Corn 17

Wheat 18

Veg 10

Fruit 5

Lucerne 50 0.1 0.1 0.2 0.8 1.2 1.6 1.7 1.6 1.1 0.7 0.1 0.1

Cotton 50 0 0 0 0.8 2.1 4.8 5.6 4.9 2.5 0 0 0

Corn 40 0 0 0 0.3 0.9 1.9 2.1 1.2 0 0 0 0

Wheat 65 0.1 0.1 0.3 1.2 2.5 2.8 0 0 0 0.5 0.2 0.1

Veg 100 0 0 0 0.9 2.0 2.5 0 1.8 1.9 1.1 0 0

Fruit 100 0 0 0.1 0.3 0.4 0.7 1.2 1.1 0.6 0.4 0.1 0

Sum ETc 0.2 0.2 0.6 4.3 9.1 14.3 10.6 10.6 6.1 2.7 0.4 0.2

Rain MCM 3.1 4.2 5.0 5.3 3.2 0.7 0.1 0 0.1 0.3 2.6 2.6

CI % 37 37 37 100 100 100 72 82 65 47 37 37

Eff Rain MCM 0.2 0.2 0.6 4.3 3.2 0.7 0.1 0 0.1 0.1 0.4 0.2

IWRc MCM 0 0 0 0 5.9 13.6 10.5 10.6 6.0 2.6 0 0

Q* MCM 11.5 10.5 19.8 45.6 48.2 46.7 36.4 21.4 14.8 14.5 13.5 12.9

Req Eff % 0 0 0 0 12 29 30 50 41 18 0 0

Legend: See Table 4.

6 IWMI. 2007. Water for food water for Life: A Comprehensive Assessment of Water Management in Agriculture, http://www.iwmi.cgiar.org/assessment/Publications/books.htm. See also W. Bastiaanssen. 2016. The water

productivity score (WPS) at global and regional level: Methodology and first results from remote sensing measurements of wheat, rice and maize. Science of the Total Environment. 575. pp. 595–611.

7 UWAD. 2006. The Relationship between Corn Grain Yield and Forage Yield. http://corn.agronomy.wisc.edu/AA/pdfs/A045.pdf.

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Figure 3: Actual evapotranspiration and wheat yield

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Figure 4: Grain yield and water productivity

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14. Table 5 replicates the analysis in Table 4 for the following values of ETa instead of ETc:

i. Wheat: ETa = 0.65ETc as estimated above from the applied research in CAWMA; ii. Corn: ETa = 0.40ETc as estimated above from the applied research in CAWMA; iii. Lucerne and cotton: Assumed ETa = 0.50ETc iv. Vegetables and fruit: Assumed ETa = 1.00ETc

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15. Table 5 indicates a plausible ISE of 50% and is likely to adequately represent the present water-scarce situation with respect to the PVIS cropping pattern, ETa and water balance etc.

D. With Project Water Balance

1. Potential Cropping Pattern

Table 6: Present PVIS with project water balance and cropping pattern

Var % Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Fallow 20

Lucerne 11

Cotton 28

Corn 13

Wheat 13

Veg 10

Fruit 5

Fallow 0 0 0 0 0 0 0 0 0 0 0 0 0

Lucerne 80 0.1 0.1 0.2 1.0 1.5 2.0 2.2 2.0 1.4 0.9 0.2 0.1

Cotton 80 0 0 0 1.0 2.7 6.0 7.0 6.1 3.1 0 0 0

Corn 80 0 0 0 0.4 1.4 3.6 3.3 1.8 0 0 0 0

Wheat 80 0.1 0.1 0.3 1.0 2.2 2.5 0 0 0 0.4 0.2 0.1

Veg 100 0 0 0 0.9 2.0 2.5 0 1.8 1.9 1.1 0 0

Fruit 100 0 0 0.1 0.3 0.4 0.7 1.2 1.1 0.6 0.4 0.1 0

Sum ETc 0.2 0.2 0.6 4.6 10.2 17.3 13.7 12.8 7.0 2.8 0.5 0.2

Rain MCM 3.1 4.2 5.0 5.3 3.2 0.7 0.1 0 0.1 0.3 2.6 2.6

CI % 29 29 29 80 80 80 57 67 54 39 39 39

Eff Rain MCM 0.2 0.2 0.6 4.2 2.5 0.5 0.1 0 0 0.1 0.5 0.2

IWRc MCM 0 0 0 0.4 7.7 16.8 13.6 12.8 7.0 2.7 0 0

Q* MCM 11.5 10.5 19.8 45.6 48.2 46.7 36.4 21.4 14.8 14.5 13.5 12.9

Req Eff % 0 0 0 1 16 36 37 60 47 19 0 0

Legend: See Table 4.

8 PVIS farmers presently irrigate high-value onion crops three or four times more frequently than other crops.

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16. The indicative with-project cropping pattern is in Table 6. This is for the present stationary climate. This is based on the following indicative plausible irrigation system operation strategy;

i. Maintain present full irrigation (ETa = 1.00ETc) of existing areas of vegetables and fruit; ii. Reduce the present irrigated cropping intensity, from 100% to 80%, by allocating 20%

of the PVIS service area to unirrigated fallow (this area can be rotated annually);

iii. Reduce the area of other crops to maximize PoW (ETa = 0.80ETc) and optimize yield; iv. Increase ISE by 20%, from 50% to 60%, requiring about 10% increases in both:

a. Main system delivery efficiency (primary to quaternary canals) and: b. Farmer field-level application efficiency;

2. Potential Productivity of Water 17. Actual crop evapotranspiration (ETa), PoW (Ya / ETa) and yield (Ya) relationships. 9 are:

i. Seasonal PoW and total production increase: a. Rapidly, with ETa, in the range 0 < ETa < 0.5ETc, but: b. Much less so in the range 0.5ETc < ETa < ETc

ii. Average ETa values vary considerably. Therefore, about 20% to 25% of the PV service area is likely to have present seasonal ETa < 0.5ETc, and:

iii. ETa limits vary considerably with crop growth stage. Therefore, if / when shortages occur at critical stages, PoW and total production reductions will be more substantial.

18. This confirms considerable potential to increase PVIS agricultural PoW (Ya / ETa). Maximum or potential crop yield (Yc) occurs at ETc. For wheat and corn, Table 4 indicates that seasonal ETc is 67.0 MCM and 94.3 MCM respectively, or nearly 500 mm and 700 mm. For these maximum ETc values, Figure 4 indicates that PoW is equal to about 1.70 kg m-3 and 1.75 kg m-3

and maximum average farmer yields (Yc) are about 8.5 T ha-1 (wheat) and 12.2 T ha-1 (corn). 19. However, depending on the crop and its growth stage, maximum PoW occurs when actual ETa is about 80% of ETc

9, 10 or optimum ETa is equal to about 400 mm (wheat) and 560 mm (corn). These values are used in the with-project PVIS cropping pattern and water balance (Table 6). For optimum ETa values, Figure 4 indicates that PoW is equal to about 1.50 kg m-3 and 1.75 kg m-3

and optimum average farmer yields (Ya) are about 6.0 T ha-1 (wheat) and 9.8 T ha-1 (corn). 20. The key DMF outcome indicator is agricultural PoW withdrawn. The baseline is 2017 and the target is 2026. This is six years (2021 – 2026 inclusive) out of the 10 years (2021 – 2016) required to reach the peak adoption rate of 84%. This was estimated, by the TRTA team, using the ADOPT tool. 11 Therefore, the DMF outcome indicator is assessed herein using 50% of the above average optimum actual crop evapotranspiration rates (ETa) and an intermediate ISE.

9 ADB. 2015. Regional: Innovations for More Food with Less Water, Technical Assistance Consultant’s Report,

https://www.adb.org/sites/default/files/project-document/189709/45072-001-tacr-05.pdf. 10Figures 3 and 4 are for multiple crops growing in multiple environments. Therefore, they are indicative but do not

reflect optimum agricultural productivity of water (PoW = Ya / ETa) for a single crop growing in a unique environment. 11CSIRO Adoption and Diffusion Outcome Prediction (ADOPT) Tool, https://research.csiro.au/software/adopt/.

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For wheat:

i. The 2017 baseline was ISE = 50%, ETa = 320 mm and yield = 4.0 T ha-1; Therefore, PoW withdrawn = 0.50 x 4.0 / 3.2 = 0.625 kg m-3;

ii. In 2030 the optimum ETa = 400 mm; iii. Therefore, the target is ISE = 55%, ETa = 360 mm, Ya = 4.95 T ha-1 Pa consumed =

4.95 / 3.6 = 1.375 kg m-3 and Pa withdrawn = 0.55 x 1.375 = 0.75 kg m-3; iv. This is reasonable as PVIS farmers, with the highest present yields, report 5.5 T ha-1; v. Therefore, PoW withdrawn will increase by 20%, from 0.635 kg m-3 to 0.75 kg m-3.

21. For corn:

i. The 2017 baseline was ISE = 50%, ETa = 280 mm and yield = 2.8 T ha-1;

Therefore, PoW withdrawn = 0.50 x 2.8 / 280 = only 0.50 kg of grain m-3. ii. In 2030, the optimum ETa = 560 mm. Therefore, the 2026 target is ISE = 55%, ETa =

420 mm, Ya = 6.72, Pa consumed = 1.60 kg m-3 and Pa withdrawn = 0.88 kg m-3, and: iii. PoW withdrawn is expected to increase by 76%, from 0.50 kg m-3 to 0.88 kg m-3.

22. PVIS farmers, with the highest present grain yields, report only 4.0 T ha-1 of corn. However:

i. Corn is presently underirrigated (ETa / ETc = 40%) compared to wheat (64%); ii. Potential corn evapotranspiration (700 mm) is also higher than wheat (nearly 500 mm); iii. Therefore, optimum corn grain yield (9.8 T ha-1) is 63% higher than wheat (6.0 T ha-1); iv. For the target corn yield (6.72 T ha-1), 20% less land will be irrigated with more water.

Therefore, the average crop yield will be a modest 0.80 x 6.72 = 5.38 T ha-1;

v. All 2,200 Jalalabad and Osh farmers, that participated in the USAID Agro Horizon Project (AHP), doubled their corn yields from an average of only 2.4 T ha-1 (in 2015) to 4.8 T ha-1 (in 2016). This involved only training and demonstrations of improved: a. Agronomy: new high-quality maize seeds, fertilizers or pesticides, and; b. Mechanization: soil preparation, harrowing, spraying, cultivation and harvesting;

vi. However, AHP did not include explicit interventions to improve agricultural PoW! 12

23. Therefore, the modern irrigated corn target is predictable and reasonable. Furthermore, it and similar potential increases in cotton and pasture PoW, provide the main potential benefit and incentive to modernize irrigated agriculture. Otherwise, it’s just another rehabilitation project.

12 https://www.usaid.gov/results-data/success-stories/new-technologies-help-farmers-double-their-maize-yields.

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II. Drought Risk Assessment

Table 7: Irrigated water balance, cropping pattern and drought risk assessment

Drought Risk Assessment Irrigated Water Balance and Cropping Pattern

Hazard p (hi)

Design irrigated agriculture water balance:

• 80% reliable monthly stream flow

• 80% reliable monthly precipitation

• Mean monthly potential evapotranspiration (ET0)

Therefore, drought occurs once in every five years, on average

Exposure e Ideally, the irrigation system and its irrigable service area

Vulnerability v The annual cropping pattern without and with climate change

Drought Risk f (p (hi), e, v) Loss of agricultural production in drought years

Adaptation NA Practical drought risk management (DRM) interventions

Sources: ADB 2017a, 13 ADB 2017b 14 and TRTA team interpretation thereof for irrigated agriculture.

24. Table 7 demonstrates that the above conventional irrigated water balances and cropping patterns are the appropriate form of drought risk assessment (DRA) for irrigated agriculture:

i. In the design case, on average, drought occurs once in every five years; ii. The 80% reliable compound water balance climate hazard is in Table 3; iii. The resulting present (stationary) climate cropping patterns are in:

a. Table 5, without the project, and: b. Table 6, with the project;

25. During project implementation, the PIC will use the following method to assess drought risk in terms of annual average damage (AAD) or average annual net value of production (NVP). First, the PIC needs to facilitate informed collective WUA member and DWR consensus regarding their acceptable of the level of reliability for which they will operate PVIS? While 80% reliability is conventional for design, its use for operation does not optimize annual average NVP or AAD. 26. Estimates of monthly streamflow discharge, potential evapotranspiration and precipitation are in Table 2. These comprise the compound climate hazard and will be verified and be used to recalculate with project water balances and cropping patterns (Table 6 for 80% reliability) at the 50%, 90%, 95%, 99%, 99.9% and 99.99% etc. reliability levels. Crop gross margins ($ ha-1) will be adjusted accordingly and used to estimate the total PVIS NVP at each frequency level. For example, if WUA members and DWR, decide to manage PVIS for 50% reliability: (i) drought starts at 50% reliability, (ii) annual damage is the difference between the NVPs at 50% reliability and at each higher level of reliability (eg 80%) and (iii) the AAD is the average of these values.

13 ADB. 2017a. Disaster Risk Assessment for Project Preparation: A Practical Guide, https://www.adb.org/sites/default/files/institutional-document/388451/drm-project-preparation-practicalguide.pdf. 14 ADB. 2017b. Natural Hazard Data: A Practical Guide, https://www.adb.org/sites/default/files/institutional-

document/387631/natural-hazard-data-practical-guide-main.pdf.

15

III. Climate Risk Assessment

A. Projections and Hazard

Table 8: RCP 8.5 projections of 2050 compound water balance climate hazard variables15

Var Unit Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Q80 m3 s-1 5.4 2.4 11.4 26.4 36.0 28.8 14.4 9.0 6.6 6.0 8.4 6.0

Q* m3 s-1 5.4 2.4 11.4 18.0 18.0 18.0 14.4 9.0 6.6 6.0 8.4 6.0

ET0 mm 26 37 58 102 147 190 205 185 144 83 43 28

P80 mm 11 27 55 68 42 25 7 2 0 2 18 33

Q* MCM 14.5 5.9 30.5 46.7 48.2 46.7 38.6 24.1 17.1 16.1 21.8 16.1

ET0 MCM 3.5 5.0 7.8 13.8 19.8 25.7 27.7 25.0 19.4 11.2 5.8 3.8

P80 MCM 1.5 3.6 7.4 9.2 5.7 3.4 0.9 0.3 0 0.3 2.4 4.5

WB80 MCM 12.5 4.5 30.1 42.1 34.1 24.4 11.8 -0.6 -2.3 4.9 18.4 16.8

Legend: See Table 3. Source: Supplementary Document 24: Detailed Climate Change Assessment (CRVA).

B. Vulnerability Assessment

27. For the present stationary climate situation, the cropping season starts in April because the mean monthly temperature in March (-4.3oC) is below (4oC). However, with climate change, mean monthly minimum temperature are projected to increase to about -1oC (February) and +6oC (March). Therefore, in 2050, the cropping season can start in March if not in February. Therefore, this section re-estimates the with-project cropping pattern and water balance for the same cropping pattern starting in March instead of April (Table 11).

C. Adaptation Assessment 28. By shifting the present stationary climate cropping pattern (Table 5), to reflect the change in cropping season with projected climate change, the PVIS with-project cropping pattern is not vulnerable to projected climate change (Table 9). In fact, as there is no reason why the same ISE (50%) cannot be attained with climate change as without it, the present with-project cropping pattern can actually be intensified in 2050. The present main canal design delivery capacity (18.0 cumec) is not a constraint, either without (Table 5) or with climate change (Table 9). IV. Project Interventions

29. The main project intervention will be to facilitate progressive development of revitalized WUGs and WUAs with the capacity to: (i) manage and solve today’s problems today and (ii) then continue to adapt to manage and solve tomorrow’s problems tomorrow. This will involve the participation of all WUA members in development and implementation of their plans to:

i. Manage water scarcity, i.e. normal system operation plans; ii. Manage drought disaster risk, with and without climate change, and: iii. Adapt main system and field-level water management to climate change;

15 These projections are not present climate estimates multiplied by the ratio of forecast and hindcast projections.

16

A. Advance Actions

30. Advance actions will include: (i) satellite image interpretation (SII), to estimate ETa, Ya and actual PoW (Ya / ETa), (ii) FAO CropWat and AquaCrop modeling, to estimate ETc, Yc and potential PoW (Yc / ETc) and (iii) FAO Rapid Appraisal Procedure (RAP) to estimate the irrigation system efficiency (ISE) from the product of the primary, secondary, tertiary and quaternary canal delivery efficiencies and farmer field-level application efficiency. During mobilization, these advance action outputs will be used to catalyze irrigated farmer water user demand for:

i. Revitalization of existing WUAs and formation of new lower-level WUGs; ii. Irrigation system modernization, to improve PoW and increase NVP, based on:

iii. WUA member appreciation of the present level of water scarcity and its implications.

B. Normal System Operation

31. The project will facilitate three system operation cycles. System operation will include the irrigation system: (i) annual cropping pattern and (ii) associated water delivery schedule. Each annual cycle will involve iterative participatory planning, implementation, monitoring, evaluation and re-planning. Key issues, for informed collective WUG member decision-making, include the:

i. Normal irrigation system operation strategy, including: ii. Level of normal system operation reliability, for example 80% or 50%? iii. Allocation of the limited water (m3) to irrigate less land with more water (m3 ha-

1)? C. Drought Risk Management

32. Either temporary or permanent rotations are a good way to manage drought risk. However, the allocation needs to be transparent, understood and agreed in advance by all WUA members and implemented consistently. An indicative water allocation and rotation plan is in Table 10.

17

Table 9: 2050 PVIS with project water balance and cropping pattern

Var % Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Fallow 20

Lucerne 11

Cotton 28

Corn 13

Wheat 13

Veg 10

Fruit 5

ET0 MCM 3.5 5.0 7.8 13.8 19.8 25.7 27.7 25.0 19.4 11.2 5.8 3.8

Lucerne Kc 0.40 0.40 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.40 0.40 0.40

Cotton Kc 0.35 0.64 1.13 1.20 1.15 0.80

Corn Kc 0.30 0.75 1.18 1.20 0.75

Wheat Kc 0.40 0.40 0.80 1.15 1.00 0.40 0.40 0.40 0.40

Veg Kc 0.75 1.10 1.05 0.75 1.10 1.05

Fruit Kc 0.20 0.20 0.45 0.45 0.60 0.90 0.95 0.70 0.70 0.20 0.20 0.30

Lucerne 80 1.1 1.6 5.9 10.5 15.0 19.5 21.1 19.0 14.7 3.6 1.9 1.2

Cotton 80 0 0 2.2 7.1 17.9 24.7 25.5 16.0 0 0 0 0

Corn 80 0 0 1.9 8.3 18.7 24.7 16.6 0 0 0 0 0

Wheat 80 1.1 1.6 5.0 12.7 15.8 0 0 0 6.2 3.6 1.9 1.2

Veg 100 0 0 5.9 15.2 20.8 0 20.8 27.5 20.4 0 0 0

Fruit 100 0.7 1.0 3.5 6.2 11.9 23.1 26.3 17.5 13.6 2.2 1.2 0.8

Fallow 20 0 0 0 0 0 0 0 0 0 0 0 0

Lucerne 11 0.1 0.2 0.7 1.2 1.7 2.1 2.3 2.1 1.6 0.4 0.2 0.1

Cotton 28 0 0 0.6 2.0 5.0 6.9 7.1 4.5 0 0 0 0

Corn 13 0 0 0.2 1.1 2.4 3.2 2.2 0 0 0 0 0

Wheat 13 0.1 0.2 0.6 1.7 2.1 0 0 0 0.8 0.5 0.2 0.2

Veg 10 0 0 0.6 1.5 2.1 0 2.1 2.8 2.0 0 0 0

Fruit 5 0 0.1 0.2 0.3 0.6 1,2 1.3 0.9 0.7 0.1 0.1 0

Sum ETc 0.2 0.5 2.9 7.8 13.9 15.2 15.0 10.3 5.1 1.0 0.5 0.3

Rain MCM 1.5 3.6 7.4 9.2 5.7 3.4 0.9 0.3 0 0.3 2.4 4.5

CI % 29 29 80 80 80 57 67 54 39 39 39 29

Eff Rain MCM 0.2 0.5 2.9 7.4 4.6 1.9 0.6 0.1 0 0.1 0.5 0.3

IWRc MCM 0 0 0 0.4 9.3 13.3 14.4 10.2 5.1 0.9 0 0

Q* MCM 14.5 5.9 30.5 46.7 48.2 46.7 38.6 24.1 17.1 16.1 21.8 16.1

Req Eff % 0 0 0 1 19 28 37 42 21 6 0 0

Legend: See Table 4.

18

Table 10: Indicative water allocation and rotation plan

Block Corn Growth Stage and Yield Response Factor (Ky)

1st 0.4 0.9 1.5 2.3 0.5 0.2

2nd 0.4 0.9 1.5 2.3 0.5 0.2

3rd 0.4 0.9 1.5 2.3 0.5 0.2

Block Priority to Receive Limited Water

1st 1st 1st 1st 1st 3rd 3rd

2nd 2nd 2nd 2nd 1st 2nd 2nd

3rd 3rd 3rd 2nd 1st 1st 1st

Source: TRTA team interpretation of FAO. 2012 16

33. The indicative water allocation and rotation plan in Table 10 is:

i. Socially equitable, as all water users receive an equal opportunity (probability) of water delivery and crop production over time (by rotating turns annually between blocks);

ii. Economically efficient, as it allocates water to the crops that are most sensitive to water-stress (ETa / ETc) over the growing season;

D. Climate Change Adaptation

34. As increasing minimum temperatures allow, the main CCA intervention will be to start the annual cropping season earlier than at present (1 April). This will minimize the impact of water shortages in August (Table 8) and allow the intensification of irrigated agriculture (tables 6 and 9).

16 FAO. 2012. Crop Yield Response to Water, http://www.fao.org/docrep/016/i2800e/i2800e.pdf.

19

Annex A: PVIS Representative Precipitation Data for Jalalabad Station

Year Jan Feb Mar Apr Jun Jul Aug Sep Sep Oct Nov Dec

1947 43 35.6 33.3 81 13 82.7 10.1 0.9 8.5 51.6 71.7 30.4

1948 29.1 33.7 118.5 92 93.5 25.2 1.2 0 5.9 36.2 11.8 125

1949 41 46.4 137.5 93 81.1 115.3 6.9 7.1 4.6 14.2 27.7 20.8

1950 54.3 18.8 71 59.5 55.9 11.7 9.1 9.9 0.1 50.2 66.1 8.3

1951 55.7 105.8 29.8 23.8 105.8 21.2 6.4 0 4.4 131.9 90.3 47.2

1952 11.1 39.9 70.7 111.2 42.1 30.3 18.1 26.5 7.8 11.2 65.6 11.1

1953 48.6 69.2 133.7 105.5 15.7 49 1.7 2.7 2.8 143.9 206.8 72

1954 52 57.3 84 64.6 22.8 70.4 67.5 14.6 6.6 0 75.1 27.7

1955 6.1 38.5 176.5 75.4 39.3 6.8 33.9 0 8.9 0 54.4 109.8

1956 22.9 104.8 107.3 57.6 52 13 0 0 5.9 0.4 13.8 50.2

1957 105.6 43.8 57.2 25.4 13 79.1 24.5 1.9 0 70 49.7 26.3

1958 54.2 39.6 103 155.7 58.6 43 17.5 6.9 1 17.5 33.9 96.3

1959 31.4 70.1 188.8 72.6 12.6 13.4 9.6 0.2 0 30.2 65.8 78

1960 57 56.2 100.2 42.4 96.9 13 2 0 45.3 38.6 83.9 8.5

1961 22.1 36.7 64.1 59.1 31.1 13.6 2.6 7.5 2.3 44.6 50.8 23.5

1962 63.1 61.5 5.7 64.6 29.9 24 5.6 0.9 2 11.2 122.3 62.3

1963 7.3 57.4 87.1 93.2 91.9 19.8 5.9 2.1 1.9 51 92.2 36

1964 31.7 71.9 92.1 71.4 77.9 6.8 0.2 0.4 2.1 0.3 11.2 7.3

1965 35 64.4 32.9 12.7 7 6.1 2 9 13 67.6 67.6 4.3

1966 59.6 62.1 172.9 47.1 73.8 7.3 2.3 20 3.6 56.7 10.1 35.4

1967 20.9 66.3 29.4 65.4 83.6 35.8 40.5 0.3 4.4 74.4 27.7 33.4

1968 40.6 15.9 79.4 69.6 40.1 23.1 3.3 0 3.5 30.2 27.8 103.8

1969 151.1 90.3 152.1 88.3 61.9 49.3 46.2 1.9 24.9 151.3 24.8 24.2

1970 31 30.1 78.9 147.6 32.3 25 11.5 10.5 8.5 17.8 22.8 87.8

1971 32 66 47.7 114.2 13.6 11.5 5.2 3.9 20.1 16.4 1.4 55

1972 68.6 66 91.5 30.8 41.1 51.7 33.1 2.8 5.5 32.4 55.6 38.9

1973 52.4 72.5 91.8 38.6 49.7 2.1 0.7 0 19.5 5.1 7.5 11.2

1974 73.2 37.5 40 39.9 31.7 7.2 3.8 17.7 12.4 28 35 12.6

1975 20.2 55.1 64.5 37.4 30.4 3.8 8.9 0.1 1.7 22.1 52.1 48.5

1976 33.1 71 101.6 92.6 58.5 22.9 1.8 0 15.9 138.1 18.1 19.4

1977 80.6 23 38.7 37.4 72.7 18.7 0.7 2.9 1.7 153.4 18.6 117.7

1978 50.4 62.3 60.3 79.9 92 22.4 0.4 0.8 0 9 69.3 59.1

1979 91.6 37.6 31.4 176.2 68.5 18.8 1.4 3.9 34.2 9.9 35.4 14.7

1980 54.7 91.8 85.8 60.1 55.9 44.5 7 0.8 6.7 8.1 61 18.8

1981 26.3 84.7 56.4 93.1 52.8 20.8 26.7 43.2 15.6 24.8 36.1 8.8

1982 19.2 44.6 62.6 16.4 31.8 3 9.7 11.7 17 71.2 71.9 3.9

1983 56.6 15.9 62.2 107.2 46.8 31.5 6.4 6.5 33.2 7.9 36.8 29.2

1984 8.7 111.5 81.5 49.2 18.3 8.4 0 0 8.1 58 101.1 89.2

20

1985 58.7 75.9 85.3 70.1 57.3 21.3 7.5 0 0 56.8 54.3 29.2

1986 16.8 16.4 38.6 54.5 29.1 97.7 0.1 0.7 5.5 42.3 61.9 85.2

1987 43 65 98.3 127.6 42.7 53.1 38.6 13.4 18.2 242.3 39.4 43.1

1988 65.2 32.8 110 61 96 7.6 3.4 1.8 0.4 42.4 2.5 61.5

1989 31.2 44.6 24.1 45.9 52.8 10.8 14 2.5 9.1 16.4 81.8 45.6

1990 78 50.2 76.8 61.4 18.2 5.2 38.8 6.6 1.7 53.5 36.3 42.9

1991 75.9 53.5 104.5 66.9 44.8 39.2 11.1 7.6 5.3 13.3 25.9 102.3

1992 46.1 53.4 69.1 125.5 93.7 25 32.1 25.1 18.3 0.8 13.1 78.1

1993 30.7 94.2 89.4 56.8 141.9 63.8 13.5 13.2 17.8 31.7 177.5 55.3

1994 51.3 85.2 63.6 54.5 30.3 5 2.4 0.7 16.9 29.4 109.5 85.8

1995 40.7 36.4 39.2 52.5 18.3 0.4 21.3 0 1.4 49.8 23.1 51.9

1996 43.2 81.4 103.4 122.4 49.1 5.1 16.4 0 2.8 14.4 28.3 22.1

1997 50.4 25.6 45.4 18.5 100. 27.6 5.2 7.9 0 0 34.9 67.1

1998 65 112.1 57.1 82.4 148 68.7 15.1 7.9 6 19.6 88.8 72.3

1999 38.9 29.8 113.1 100.4 28.9 24.7 19.2 1.1 18.8 13.1 120.1 23.7

2000 56.4 20.8 26.3 68.6 6.9 9.9 4.1 1.6 15.4 112.3 68.9 30.3

2001 61.4 31.8 29.1 17.7 78.2 12.5 30.2 13.1 3 61.8 56.8 47.1

2002 76.1 35.9 55.4 87.8 66 32.1 10 0.9 7.9 18.4 28.3 99.7

2003 14.9 70.1 105.8 168.8 61.3 23.6 5.4 6.9 19.7 59.3 106.7 37.5

2004 40.5 17.1 121.4 46 33.1 21. 19.8 23.2 6.4 52.7 33.3 78.2

2005 47.3 54.3 77.4 77.4 66 93.2 0 1.3 0 31.3 32.6 44.8

2006 130.5 77.8 21.8 68.4 27 5.9 4.8 0 10.6 41.6 41.5 28

2007 24.1 18.8 76.3 19.9 48.5 2.5 18.4 1 0 0 31 63.8

2008 36.1 34.4 6.2 44 25.9 0 4.2 0 3.8 69.1 68.6 47

2009 22.5 56.6 58.9 112.3 129.8 69 30.3 0 3.4 2 63.9 63.2

2010 66.1 105.9 118.1 42.5 55.5 146.1 18.4 11.8 30.9 32.4 20.2 22.6

2011 6 98 62.3 37.5 41.4 12.3 0 9.1 0 63.9 158 38.9

2012 32.9 49.2 62.7 75.7 35.1 52.9 5.6 0 0.8 0 83.6 53.8

2013 23.4 63.4 22.9 68.2 43.2 26.1 14 7.5 3.2 8.4 23.7 63.5

2014 56.1 66.5 61.5 87 6.2 26 0 1.8 2.4 94.3 108 37.9

2015 38.2 71.5 113.1 68.7 66.1 44.3 1.6 43.8 9.1 79.7 67.1 67

2016 38 8.4 54.2 49.2 115.5 11.4 27.4 0 0.8 80.3 58 143.2

2017 55.2 120.5 43.8 119.7 26.6 23.5 7.6 8.6 36.3 82.9 13 25.1

Natural logarithm (ln) values

Mean 3.67 3.90 4.16 4.14 3.76 2.84 1.47 0.17 1.02 2.77 3.72 3.64

SD 0.65 0.56 0.65 0.56 0.71 1.42 2.20 2.99 2.43 2.49 0.89 0.80

Frequency (F) estimates (log-normal distribution)

R (%) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

50 39.1 49.4 63.9 62.8 43.0 17.1 4.3 0.8 2.8 15.9 41.1 38.3

80 22.6 30.8 36.8 39.2 23.6 5.2 0.7 0.1 0.4 2.0 19.4 19.4

Sources: KyrgyzHydromet (data) and TRTA (log-normal frequency estimates). Legend: R = reliability (probability of exceedance) and SD = standard deviation.

21

Annex B: PVIS Representative Streamflow Data for Tentek Sai Station

Year Jan Feb Mar Apr Jun Jul Aug Sep Sep Oct Nov Dec

1938 7.15 7.77 10.20 44.60 39.50 29.20 18.30 11.80 8.03 7.37 7.86 7.61

1939 6.42 8.14 11.40 26.90 61.90 49.00 30.50 14.00 9.85 9.01 9.42 7.79

1940 6.23 7.10 11.50 28.80 90.60 89.60 28.40 15.40 11.30 14.70 15.70 11.60

1941 10.70 11.90 27.00 59.70 80.40 45.80 21.30 14.90 10.60 9.52 11.30 10.70

1942 9.20 8.94 23.20 70.20 124.00 76.80 36.60 17.60 11.20 9.84 10.00 8.68

1943 7.94 8.54 16.30 48.80 92.80 72.80 36.30 17.60 11.90 10.60 10.50 10.40

1944 9.09 9.09 18.00 46.00 54.70 35.70 22.50 13.50 9.68 9.92 12.10 8.29

1945 7.18 6.62 12.40 53.10 75.50 72.40 36.50 18.70 12.20 9.67 10.90 9.22

1946 8.05 9.55 19.80 102.00 85.80 53.30 29.50 17.80 12.30 11.60 13.30 11.90

1947 11.40 11.20 19.20 36.00 48.40 50.10 28.20 16.50 13.00 13.00 21.20 13.10

1948 12.10 11.90 16.30 80.20 124.00 71.80 42.00 22.00 16.30 13.20 12.10 12.10

1949 10.80 11.20 15.80 82.20 148.00 102.00 47.10 22.80 16.60 13.60 12.40 10.50

1950 9.77 9.50 13.50 27.30 73.30 50.50 25.60 16.30 12.30 11.10 12.20 10.10

1951 9.05 8.81 14.90 38.80 86.10 61.60 38.50 22.20 14.90 22.90 29.00 18.90

1952 14.30 14.30 20.70 108.00 117.00 92.70 55.80 29.20 19.70 15.40 14.00 13.40

1953 12.50 13.80 26.80 59.00 126.00 76.40 33.30 19.70 14.60 18.00 20.40 18.60

1954 15.00 14.10 26.70 0.00 0.00 106.00 91.90 55.20 28.50 20.00 16.40 14.70

1955 13.10 13.10 27.80 57.90 82.80 57.00 33.70 21.20 16.00 13.40 13.00 13.10

1956 12.40 12.50 20.70 74.70 99.90 60.10 38.30 18.10 13.90 12.00 10.30 8.70

1957 8.27 8.38 18.50 36.20 45.00 55.80 43.50 22.10 14.50 11.40 11.10 9.44

1958 8.61 8.83 25.40 96.10 95.20 92.90 62.80 28.70 16.60 15.60 13.00 11.50

1959 9.87 8.99 20.70 134.00 102.00 82.50 45.60 22.90 14.80 12.10 11.70 10.80

1960 10.50 12.00 19.00 79.20 180.00 134.00 65.80 24.70 17.20 15.00 15.10 11.20

1961 9.11 8.11 17.00 54.10 57.20 30.30 16.50 11.80 8.43 7.69 7.32 6.95

1962 6.75 7.63 14.60 31.80 48.80 40.10 23.30 13.30 9.88 8.34 9.24 8.84

1963 8.42 9.89 17.90 63.20 90.30 73.00 30.80 16.60 11.40 10.20 11.10 9.83

1964 8.49 7.95 21.40 61.20 78.90 66.00 45.50 23.30 14.00 10.20 8.63 7.68

1965 7.27 7.17 9.25 22.30 36.20 28.20 16.90 10.80 8.64 12.00 25.70 14.80

1966 10.00 10.30 24.90 58.90 96.70 75.00 31.80 18.10 10.90 9.28 7.24 6.65

1967 6.21 6.03 10.80 38.70 64.40 48.10 29.20 13.40 8.58 8.28 7.58 6.47

1968 6.16 5.75 12.70 41.10 56.10 55.70 27.90 14.20 9.71 8.07 7.74 7.16

1969 6.60 6.58 30.70 84.40 196.00 144.00 81.00 41.00 26.20 33.20 43.80 21.30

1970 14.90 14.90 21.20 79.50 101.00 62.60 37.60 22.90 14.20 10.70 10.80 11.10

1971 10.00 8.63 24.40 82.70 84.10 57.70 28.50 16.10 11.70 9.78 8.90 8.02

1972 7.60 6.92 10.40 50.30 84.90 80.50 41.10 22.90 13.80 13.20 16.40 12.20

1973 9.69 10.10 16.90 67.90 95.80 60.40 26.50 15.60 11.30 9.83 8.27 6.72

1974 6.47 6.49 11.00 21.00 21.20 19.10 10.90 9.15 8.89 8.40 7.91 7.20

1975 6.35 6.19 12.50 40.30 33.40 27.00 14.20 7.74 5.75 5.58 5.71 5.43

1976 5.17 5.18 8.03 51.80 55.30 32.40 16.60 9.23 7.39 9.79 11.20 7.89

22

1977 6.93 6.42 13.40 35.10 38.30 34.50 15.80 10.50 8.34 9.09 11.20 8.46

1978 7.98 8.15 12.90 57.40 61.70 51.50 25.60 13.70 9.29 8.79 8.17 8.79

1979 8.03 8.75 13.90 80.70 76.00 66.20 34.70 18.80 13.20 10.20 9.61 8.16

1980 7.44 7.37 10.90 65.40 86.10 51.70 25.00 13.20 7.94 7.07 8.47 9.04

1981 7.06 6.90 17.20 55.50 80.20 57.40 35.00 31.70 20.40 17.10 13.90 11.30

1982 9.37 8.88 13.00 51.50 39.60 25.50 22.00 15.10 12.90 19.10 17.60 12.60

1983 10.30 9.82 12.20 40.30 80.10 63.70 30.80 17.70 12.50 10.60 12.00 11.20

1984 8.53 7.04 15.00 45.20 48.80 45.90 17.40 13.20 11.10 10.60 11.10 10.60

1985 10.30 10.90 21.40 92.40 116.00 79.30 34.30 17.20 12.90 11.70 12.40 13.60

1986 10.70 8.58 12.00 39.40 57.90 58.90 30.00 18.10 11.80 13.80 11.50 15.60

1987 11.70 15.80 43.30 102.00 134.00 129.00 80.40 53.80 30.40 30.30 40.20 26.90

1988 23.90 21.90 35.10 90.60 135.00 114.00 57.80 32.60 17.90 13.10 12.70 11.00

1989 9.16 7.71 13.90 25.40 38.10 39.10 21.80 14.40 9.64 9.84 9.67 9.85

1990 7.97 8.00 22.50 63.80 113.00 66.60 28.20 15.50 11.00 11.10 13.70 9.77

1991 7.62 8.26 13.00 61.80 65.30 60.90 33.90 17.40 12.00 11.20 8.98 8.91

1992 8.39 8.53 11.60 51.90 107.00 86.70 40.60 19.70 13.70 10.70 7.97 7.55

1993 7.52 8.01 8.81 54.90 97.60 90.70 57.60 44.50 24.30 11.00 13.50 12.90

1994 12.20 10.80 29.50 74.30 141.00 87.20 50.30 16.90 7.66 9.47 8.26 8.59

1995 9.61 10.10 15.00 23.40 37.30 26.00 24.10 16.90 7.66 9.47 8.26 8.59

1996 9.93 11.40 17.20 69.90 122.00 86.80 56.10 39.30 12.10 11.20 9.94 10.00

1997 9.79 10.02 18.21 55.10 81.95 63.68 35.87 19.92 13.16 12.21 12.74 10.84

1998 7.25 9.33 12.70 49.90 91.40 81.20 45.80 20.80 14.30 12.10 9.36 9.08

1999 8.52 11.10 15.00 58.90 117.00 86.20 60.90 28.20 16.20 12.50 19.10 24.90

2000 28.30 33.20 44.60 47.80 73.00 50.80 24.10 23.60 19.20 22.00 26.00 24.50

2001 27.10 26.00 12.30 22.70 37.00 25.30 18.90 12.00 9.58 13.50 17.50 12.40

2002 12.00 13.70 19.00 56.70 68.30 85.40 58.50 44.00 20.00 10.10 9.76 9.26

2003 8.80 8.22 20.30 73.40 91.80 76.00 46.00 21.70 16.50 13.30 15.10 15.20

Natural logarithm (ln) values

Mean 2.23 2.25 2.82 3.92 4.27 4.09 3.50 2.94 2.54 2.46 2.49 2.36

SD 0.33 0.34 0.37 0.64 0.69 0.44 0.44 0.41 0.33 0.32 0.39 0.33

CV 0.15 0.15 0.13 0.16 0.16 0.11 0.13 0.14 0.13 0.13 0.16 0.14

Frequency (F) estimates (log-normal distribution)

R (%) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

50 9.3 9.5 16.8 50.5 71.9 59.8 33.0 18.8 12.6 11.7 12.0 10.6

80 7.1 7.2 12.3 29.3 40.1 41.3 22.7 13.4 9.5 8.9 8.6 8.0

90 6.2 6.2 10.5 22.1 29.5 34.0 18.7 11.2 8.2 7.8 7.3 6.9

95 5.5 5.5 9.1 17.5 22.9 29.0 15.9 9.6 7.3 6.9 6.3 6.1

99 4.4 4.3 7.1 11.3 14.3 21.5 11.7 7.3 5.8 5.6 4.8 4.9

99.9 3.4 3.4 5.3 6.9 8.4 15.4 8.4 5.3 4.5 4.4 3.6 3.8

99.99 2.8 2.7 4.2 4.6 5.4 11.7 6.3 4.1 3.6 3.6 2.8 3.1

Sources: KyrgyzHydromet and GRDC https://www.bafg.de/GRDC/EN/Home/homepage_node.html (data) and TRTA. Legend: CV = coefficient of variation, R = reliability (probability of exceedance) and SD = standard deviation.