Table 1 A scheme of seven mainstream and emerging water-saving techniques

From: Water-saving strategies across prefectures should target the manufacturing and agriculture sectors in China

Sub-sector

Type

Measure or technique

Definition

Saving potential (%)

Current status or area

Feasibility

Prospect (↑↓)

Cost, expenses for applications ($)

Optimal water use amount (m3)

Agricultural irrigation

Micro-irrigation

Drip irrigation79,119,120,121: Subsurface drip (SSD); surface drip (SD)

40% in soil surface wetted79,80

50–80a

Small area and expansion

Fixed investment: 2200 per ha, plus 880 per ha per year for mulch etc. consumableb

1800 per ha (winter wheat)122, 5907 (corn)

Continuous expansion, to be leading, with fertilizer & plastic mulch techniques79,80,119

Sprinkler irrigation

60% in soil surface wetted79,80

30–60

485 k ha for wheatc

Cost higher than benefit; 75% irrigation time shortened.

N.A.

To decline in cultivated area

Bubble irrigation

N.A.

30

N.A.

N.A.

N.A.

N.A.

Irrigation through pipelines

Low pressure pipelines

N.A.

15–30

11,517 k ha

N.A.

N.A.

N.A.

Canal seepage control

Canal leakage control

N.A.

15–30

N.A.

N.A.

N.A.

N.A.

Furrow & canal

Canal & furrow

80%79,80, usually based on a constant interval83, without moisture monitor

15

Dominating in China79,80

N.A.

6822 per ha (corn)

To sharply decrease in cultivated area

Industrial power generation

Water recirculation cooling

Wet towers

Transition from single-pass to recirculating-cooling

97%, from 168 liters to 5 of water abstraction per kwh68

Less than 10% thermal plantsd

Total generation costs at 0.05 per kwh36,123

159 million for electricity & hot water supply

Substantial room to reduce17

  1. Full names of sector are indicated by & for short, throughout the paper.
  2. Please see Supplementary Discussion 2 on technology cost and water policy.
  3. N.A. denotes none-available data at the current stage.
  4. aThere is no substantial gap in water-saving potential between SSD and SD. Data are from Tianjin in 2023121.
  5. bFor Zhangbei county in Hebei province, north China.
  6. cData is in 2014.
  7. dFor Suzhou, in Jiangsu province, east China.
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