The phrase "average surface water" is correct and usable in written English.
It can be used in contexts related to environmental science, hydrology, or discussions about water quality and availability.
Example: "The study measured the average surface water temperature over the course of the year to assess climate change impacts."
Alternatives: "mean surface water" or "typical surface water".
That island's maximum monthly average surface water temperature is 28.5°C; it was 30.2°C for the month of September.
The average surface water stress Index was estimated as 0.0385 and 0.150 for the years 2000 and 2050, respectively, and the difference is significant (p = 0.00043).
The average surface water quality parameters of rivers and reservoirs were analyzed separately during pre- and post-monsoon periods to ascertain the trend of contaminations (Fig. 5a, b).
The average surface water resource of the whole province is 68.608 billion m3, and the average groundwater resource is 28.687 billion m3.
The draft version 4.0 of the Guidance Chapter R.7b Endpoint specific guidance [16] states that "New simulation studies should be conducted at environmentally relevant temperatures namely at 12 °C as this is seen as the average surface water temperature for the European Union (9 °C for sea water).
In addition, average surface water temperatures have already increased by 0.7°C and may rise an additional 3°C by the end of this century.
Given the relative importance of mountain island forest in this semi-arid landscape in terms of its contribution to area-average surface water and carbon exchange, the strong and somewhat unusual coupled seasonal cycles, this forest ecosystem likely has hitherto unrecognized implication for the seasonality of the regional-scale water and carbon cycle.
The average grain size and mean surface water pH were significantly different between the two floodplain systems.
(Cooler-than-average surface waters are depicted in shades of blue, image from late July and early August 2007).
Table 3 Average annual surface water inflow upstream (based on 20 years data) River or stream Average annual flow (million m3) Tukituki 126.9 Waipawa 264.1 Avoca 9.4 Tukipo 11.6 Mangatewai 27.8 Makaretu 40.9 Porangahau 12.9 Maharakeke 10.3 Total 503.9.
Groundwater resources account for about 20% (4173 hm3), of this average while surface water account for 80% (18,248 hm3) of the total.
