222 VALUATION, DEPRECIATION AND THE RATE-BASE 
are other similar reservoir properties available for alternative 
use. The time when the utilization of the property is a neces- 
sity, if this time can be definitely or even approximately fixed, 
will affect its market value. The value will be higher after 
actual construction has demonstrated that a reservoir will hold 
water than before. If there have been any judicial determina- 
tions of the market value or of the value for rate-fixing purposes 
of the property to be valued or of similarly situated or otherwise 
comparable property or if valuations thereof have been made 
by authorities charged with the regulation of rates or by other 
public authorities, all such determinations will have an effect 
upon the market and would be given consideration by a prudent 
purchaser. They are also, therefore, proper elements for con- 
sideration by an appraiser. The cost of the lands In a site 
already acquired is a factor that should be given due weight 
with proper allowance for the circumstances attending the pur- 
chases. Appreciation or depreciation that may have taken 
place subsequent to such purchase may also have to be given 
consideration. 
~The value of a parcel of land which is required in connection 
with others to make a reservoir site available is, as above stated, 
worth less by itself than it will be when united with other tracts 
into the one holding which makes the development possible. 
While the individual tract is reservoir land and due to this fact 
may have acquired a market value in excess of the value which 
it would have if not located in a reservoir site, this excess value 
would be estimated by a prudent purchaser at less than the 
excess value which it acquires when brought into the same 
ownership as all the rest of the lands which make the storage 
of water possible. Atihow much less it should be valued can- 
not be stated with any degree of confidence for general guid- 
ance. And yet it may tentatively be suggested that the party 
who assembles the property should get the benefit of at least 
one half and, in many cases, much more than this proportion 
of the excess of its value, in the constructed reservoir, over its 
value for ordinary uses.