Indicator 6.4.1 Change in water-use efficiency over time

Goal 6: Ensure availability and sustainable management of water and sanitation for all

Target 6.4: By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity

Indicator 6.4.1: Change in water-use efficiency over time

May 2024

6.4.1: Change in water-use efficiency over time 6.1.1: Proportion of population using safely managed drinking water services 6.3.1: Proportion of wastewater safely treated 6.6.1: Change in the extent of water-related ecosystems over time 6.5.1: Degree of integrated water resources management implementation (0-100) 2.4.1: Proportion of agricultural area under productive and sustainable agriculture 15.3.1: Proportion of land that is degraded over total land area 1.5.1: Number of deaths, missing persons and persons affected by disaster per 100,000 people [a] 11.5.1: Number of deaths, missing persons and persons affected by disaster per 100,000 people [a

Kenya National Burau Of Statistics

Senior Manager

Food Monitoring, Nutrition and Environment Statistics

Compilation of Environment and Natural Resources Statistics

+254-735-004-401, +254-202-911-000, +254-202-911-001

P.O. Box 30266–00100 GPO NAIROBI

dps@knbs.or.ke

Definition:

Change in water use efficiency over time (CWUE): The change in the ratio of the value added to the

volume of water use, over time.

Last updated: 2023-05-15

Water Use Efficiency (WUE) is defined as the value added of a given major sector1 divided by the volume

of water used. Following the United Nations International Standard Industrial Classification of All

Economic Activities ISIC 4 coding , sectors are defined as:

1. agriculture; forestry; fishing (ISIC A), hereinafter “agriculture”;

2. mining and quarrying; manufacturing; electricity, gas, steam and air conditioning supply;

constructions (ISIC B, C, D and F), hereinafter “MIMEC”;

3. all the service sectors (ISIC E and ISIC G-T), hereinafter “services”.

Concepts:

• Water use: water that is received by an industry or households from another industry or is

directly abstracted. [SEEA-Water (ST/ESA/STAT/SER.F/100), par. 2.21]

• Water abstraction: water removed from the environment by the economy. [SEEA-Water

(ST/ESA/STAT/SER.F/100), par. 2.9]

• Water use for irrigation (km³/year)

o Annual quantity of water used for irrigation purposes. It includes water from renewable

freshwater resources, as well as water from over-abstraction of renewable groundwater

or abstraction of fossil groundwater, direct use of agricultural drainage water, (treated)

wastewater, and desalinated water. [AQUASTAT Glossary]

• Water use for livestock (watering and cleaning) (km³/year)

o Annual quantity of water used for livestock purposes. It includes water from renewable

freshwater resources, as well as water from over-abstraction of renewable groundwater

or abstraction of fossil groundwater, direct use of agricultural drainage water, (treated)

wastewater, and desalinated water. It includes livestock watering, sanitation, cleaning of

stables, etc. If connected to the public water supply network, water used for livestock is

included in the services water use. [AQUASTAT Glossary]

• Water use for aquaculture (km³/year)

o Annual quantity of water used for aquaculture. It includes water from renewable

freshwater resources, as well as water from over-abstraction of renewable groundwater

or abstraction of fossil groundwater, direct use of agricultural drainage water, (treated)

wastewater, and desalinated water. Aquaculture is the farming of aquatic organisms in

inland and coastal areas, involving intervention in the rearing process to enhance

production and the individual or corporate ownership of the stock being cultivated.

[AQUASTAT Glossary]

• Water use for the MIMEC sectors (km³/year)

o Annual quantity of water used for the MIMEC sector. It includes water from renewable

freshwater resources, as well as over-abstraction of renewable groundwater or

abstraction of fossil groundwater and use of desalinated water or direct use of (treated)

wastewater. This sector refers to self-supplied industries not connected to the public

• Water use for the services sectors (km³/year)

o Annual quantity of water used primarily for the direct use by the population. It includes

water from renewable freshwater resources, as well as over-abstraction of renewable

groundwater or abstraction of fossil groundwater and the use of desalinated water or

direct use of treated wastewater. It is usually computed as the total water used by the

public distribution network. It can include that part of the industries, which is connected

to the municipal network. [AQUASTAT Glossary. To be noted that in AQUASTAT, the

sectors included in “services” are referred to as “municipal”]

• Value added (gross)

o Value added is the net output of a sector after adding up all outputs and subtracting

intermediate inputs. It is calculated without making deductions for depreciation of

fabricated assets or depletion and degradation of natural resources. The industrial origin

of value added is determined by the International Standard Industrial Classification

(ISIC), revision 4. [WB Databank, metadata glossary, modified]

• Arable land

o Arable land is the land under temporary agricultural crops (multiple-cropped areas are

counted only once), temporary meadows for mowing or pasture, land under market and

kitchen gardens and land temporarily fallow (less than five years). The abandoned land

resulting from shifting cultivation is not included in this category. Data for “Arable land”

are not meant to indicate the amount of land that is potentially cultivable. [FAOSTAT]

• Permanent crops

o Permanent crops are the land cultivated with long-term crops which do not have to be

replanted for several years (such as cocoa and coffee); land under trees and shrubs

producing flowers, such as roses and jasmine; and nurseries (except those for forest

trees, which should be classified under "forest"). Permanent meadows and pastures are

excluded from land under permanent crops. [FAOSTAT]

• Proportion of irrigated land on the total cultivated land

o Total harvested irrigated crop area, expressed in percentage. Area under double

irrigated cropping (same area cultivated and irrigated twice a year) is counted twice

USD/M3

System of Environmental-Economic Accounting for Water (SEEA-water)

SEEA-water is used to define the concept of “water use” in the context of this indicator, and to describe

the water flows among users.

International Standard Industrial Classification of All Economic Activities, revision 4

ISIC-4 is used as the standard for the definition of the economic sectors

Ministry of Water, Sanitation and Irrigation, UN Water , FAO

Data collection is done through FAO's global information system on water and agriculture (AQUASTAT) and the AQUASTAT questionnaire on water and agriculture. The data collection process relies on a network of National Correspondents, officially nominated by their respective countries, in charge of the provision of official national data to AQUASTAT

Data are collected every year through the AQUASTAT network of National Correspondents

Data are released every year, usually in February following the UNSD collection schedule.

Ministry of Water, Sanitation and Irrigation, UN Water , FAO

Kenya National Bureau of Statistics

Kenya National Bureau of Statistics is mandated to collect, compile, analyze, publish and disseminate official statistics for public use.

The rationale behind this indicator consists in providing information on the efficiency of the economic and social usage of water resources, i.e., value added generated by the use of water in the main sectors of the economy, and distribution network losses. The distribution efficiency of water systems is implicit within the calculations and could be made explicit if needed and where data are available

The corrective coefficient, Cr, for the agricultural sector is needed in order to focus the indicator on the irrigated production. This is done for two main reasons: ▪ To ensure that only runoff water and groundwater (so-called blue water) are considered in computing the indicator; ▪ To eliminate a potential bias of the indicators, which otherwise would tend to decrease if rainfed cropland is converted to irrigated.

Computation Method:

Water use efficiency is computed as the sum of the three sectors listed above, weighted according to the proportion of water used by each sector over the total use. In formula:

Where:

WUE = Water use efficiency

A_we = Irrigated agriculture water use efficiency [USD/m³]

M_we = MIMEC water use efficiency [USD/m³]

S_we = Services water use efficiency [USD/m³]

P_A = Proportion of water used by the agricultural sector over the total use

P_M = Proportion of water used by the MIMEC sector over the total use

P_S = Proportion of water used by the service sector over the total use

The computing of each sector is described below.

Water use efficiency in irrigated agriculture is calculated as the agricultural value added per agricultural water use, expressed in USD/m³.

In formula:

Where:

A_we = Irrigated agriculture water use efficiency [USD/m³]

GVA_a = Gross value added by agriculture (excluding river and marine fisheries and forestry) [USD]

C_r = Proportion of agricultural GVA produced by rainfed agriculture

V_a = Volume of water used by the agricultural sector (including irrigation, livestock and aquaculture) [m³]

The volume of water used by the agricultural sectors (V) is collected at country level through national records and reported in questionnaires, in units of m³/year (see example in AQUASTAT http://www.fao.org/nr/water/aquastat/sets/aq-5yr-quest_eng.xls). Agricultural value added in national currency is obtained from national statistics, converted to USD and deflated to the baseline year.

C_r can be calculated from the proportion of irrigated land on the total Arable land and Permanent crops (hereinafter “cultivated land”, as follows:

Where:

A_i = proportion of irrigated land on the total cultivated land, in decimals

0.563 = generic default ratio between rainfed and irrigated yields

More detailed estimations are however possible and encouraged at country level.

Water efficiency of the MIMEC sectors (including power production): MIMEC value added per unit of water used for the MIMEC sector, expressed in USD/m³.

In formula:

Where:

M_we = Industrial water use efficiency [USD/m³]

GVA_m = Gross value added by MIMEC (including energy) [USD]

V_m = Volume of water used by MIMEC (including energy) [m³]

MIMEC water use (V_m) is collected at country level through national records and reported in questionnaires, in units of m³/year (see example in AQUASTAT http://www.fao.org/nr/water/aquastat/sets/aq-5yr-quest_eng.xls). MIMEC value added is obtained from national statistics, deflated to the baseline year.

Services water supply efficiency is calculated as the service sector value added (ISIC 36-39 and ISIC 45-98) divided by water used for distribution by the water collection, treatment and supply industry (ISIC 36), expressed in USD/m³.

In formula:

Where:

S_we = Services water use efficiency [USD/m³]

GVA_s = Gross value added by services [USD]

V_s = Volume of water used by the service sector [m³]

Data on volumes of used and distributed water are collected at country level from the municipal supply utilities records and reported in questionnaires, in units of km³/year or million m³/year (see example in AQUASTAT http://www.fao.org/nr/water/aquastat/sets/aq-5yr-quest_eng.xls). Services value added is obtained from national statistics, deflated to the baseline year.

Change in water use efficiency (CWUE) is computed as the ratio of water use efficiency (WUE) in time t minus water use efficiency in time t-1, divided by water use efficiency in time t-1 and multiplied by 100:

It must be noted that computing the indicator in an aggregated manner, i.e. total GDP over total water use, would lead to an overestimation of the indicator. That is due to the fact that, for the agricultural sector, only the value produced under irrigation has to be counted in calculating the indicator. Hence, the sum of the value added of the various sectors used in these formulas is not equivalent to the total GDP of the country.

The Kenya National Bureau of Statistics is ISO certified based on 9001:2015 Standard requirements. The processes of compilation, production, publication and dissemination of data, including quality control, are carried out following the methodological framework and standards established by the KNBS, in compliance with the Internationally acceptable standards

The KNBS adheres to Kenya Statistical Quality Assurance Framework (KesQAF) that underlines principles to be assured in managing the statistical production processes and output.

Data consistency and quality checks are conducted through Technical Working Groups (TWGs) before publication and dissemination.

The processes of compilation, production, publication and dissemination of data, including quality control are subjected to a set criteria and standards to ensure conformity.

The data is available at the National level by Residence and Type of improved toilet/latrine facility

No deviation