The use of rivers as a water source is a topic that often comes up when evaluating a natural resource as a water supply for a plant. The question is simple, but the answer requires connecting several points in UNI EN 12845.
Table of Contents
The question (in practice)
When we talk about “installing inlet pipes directly in the riverbed,” we usually mean routing the inlet line(s) from the pump(s) “into the river” without any intermediate structures. This solution may seem straightforward, but it must be evaluated in light of the requirements for water quality and system reliability.
Where UNI EN 12845 permits a river as a water source
UNI EN 12845 specifies the use of a river as a water source (see section 3.33). This clarifies that “river” is included among the sources considered.
In practical terms: the issue is not “whether a river can be used,” but how it can be used in a way that is consistent with the other requirements of the same rule.
The key constraint: water quality (section 8.1.2)
UNI EN 12845 itself (section 8.1.2) requires that:
- the water must not contain fibrous substances; or
- other suspended material that could cause deposits inside the system’s pipes.
This point is crucial because it shifts the focus from the “mechanical” aspect of the work (whether or not there is a pipe in the riverbed) to the system’s expected performance over time: if deposits build up in the pipes, performance may be compromised.
Why River Water Is a Sensitive Issue
The text points out that river water typically carries a significant amount of sediment. This sediment transport can:
- interfere with its operation; or
- damage the fire pump-sets.
This consideration is directly related to the requirement in section 8.1.2: the risk is not theoretical, but stems from the presence of material that can accumulate or cause problems for the equipment.
The Operational Response: What the Rules Stipulate Regarding “INEXHAUSTIBLE POWER SOURCES” (Section 9.4)
For INEXHAUSTIBLE WATER SOURCES, UNI EN 12845 (section 9.4) requires that a socket be installed between the riverbed and the pumps.
So, connecting the dots:
- The river can be used as a water source (3.33);
- However, the water must meet a “cleanliness” requirement with respect to fibrous substances and suspended solids that cause deposits (8.1.2);
- And, specifically to handle the typical case of a river (solid transport), a socket is provided between the riverbed and the pumps for inexhaustible water sources (9.4).
What must the socket include (according to the text)?
The intake structure specified in section 9.4 must include:
- a sedimentation zone; and
- an inlet zone.
This configuration serves to “separate” the river environment from the pumps by introducing an intermediate passage that addresses the client requirements regarding the presence of suspended solids and the risk of sediment buildup.
The text also states that readers should refer to Figure 5 of the cited standard for the diagram.
So: Can I place the inlet lines directly in the riverbed?
In light of the points mentioned above, “direct installation in the riverbed” is an option that risks failing to address the issue of sediment transport typical of rivers and the requirement that the water not contain suspended solids that could cause deposits.
In other words, the recommended approach is to install a socket between the riverbed and the pumps, incorporating sedimentation and inlet, as is standard for inexhaustible water sources.
Conclusion
The river can be used as a water source or supply, but the UNI EN 12845 standard requires attention to water quality and, for inexhaustible water sources, specifies the installation of an intake structure with a sedimentation zone and an inlet zone. This approach reduces the risk that suspended solids will interfere with or damage the fire-fighting pump-sets and that deposits will form in the piping.
