The Lao Alas — also called the Woi ni Agoesein in the Gajo language — is the principal river of the Alas valley of central Atjeh, rising on the southern slopes of the G. Loser (3,520 m) in the Wilhelmina gebergte and flowing south-eastward through the groote Westelijke lengtedal to its confluence with the Lae Renoen and the Simpang Kin i, by which name it reaches the Indian Ocean at Singkel. In the Encyclopaedisch Bureau’s Sumatra survey (1917), the Lao Alas is the principal hydrographical artery of the central-Atjeh hoogvlakte, and the river whose stroomgebied includes the Laut Tawar lake and the Ketol high plateau.
Course
The Bureau’s Hoofdstuk I describes the Lao Alas as rising “op de Zuidelijke hellingen van den G. Loser (70), in Zuid-Oostelijke richting het Westelijke lengtedal doorstroomt, tot zij de Lae Renoen opneemt, welke komende van den Poesoek Boehit (59) het water van de hoogvlakte der Pepagan Pak-Pak afvoert.” The Lao Alas’s right-bank tributary, the Lao Bengap, rises on the eastern slopes of the Deleng Siboeatan (60) and flows along the eastern foot of the Wilhelmina gebergte through the hoogvlakte der Karo-Bataks to its confluence with the Lae Renoen at Kota Bangoen.
After its confluence with the Lae Renoen, the Lao Alas takes in the Lae Mbelin (draining the hoogvlakte der Kepas Pak Pak) and the Lae Koembi (draining the hoogvlakte der Sim Sim Pak Pak), “om dan als Simpang Kin i de Westelijke Barisanketenen te doorbreken en bij Singkel den Indischen Oceaan te bereiken.” The Lao Alas thus passes, in its lower course, under the name Simpang Kin i, through the Westelijke Barisan to Singkel — the same Simpang Kin i name that is also borne by a separate river of the Oostkust van Atjeh (not to be confused, the Bureau notes, with this one).
The Alas valley as the southern approach to central Atjeh
The Lao Alas’s stroomgebied — the Alas valley — is the principal southern approach to the central-Atjeh hoogvlakte. The Bureau’s account locates the Lao Alas between the Wilhelmina gebergte to the north and the Gajoesche Centraalgebergte to the south, with the Laoet Tawar lake (at Takengon) and the Ketol high plateau lying within the stroomgebied of the river’s upper tributaries. The Alas valley’s role as the southern approach to central Atjeh is the geographical foundation of its strategic role in the Japanese invasion of March 1942: the valley was the designated refuge of the 2de hoofdgroep’s planned guerrilla, and the Goenoeng Setan pass at the head of the valley was the strategic choke-point of the Dutch central-Atjeh defence.
Significance
The Lao Alas is, in the Bureau’s Sumatra survey, the principal hydrographical artery of the central-Atjeh hoogvlakte, and the river whose stroomgebied defines the geographical and strategic contours of the Alas valley. The Bureau’s emphasis on the Lao Alas’s course through the groote Westelijke lengtedal, on its confluence with the Simpang Kin i, and on the Laoet Tawar and Ketol hoogvlakte within its stroomgebied, frames the Lao Alas as the geographical foundation of the central-Atjeh hoogvlakte — the river whose valley defined the Dutch colonial state’s central-Atjeh bivaks at Takengon, Blangkedjeren and Kotatjane, and whose stroomgebied would form the theatre of the capitulation of 28 March 1942.
See Also
- De Buitenbezittingen, Deel II, Aflevering 1
- Atjehrivier
- Kroeëng
- Kroeëng Wojla
- Lae Renoen
- G. Loser
- Wilhelmina gebergte
- Gajoesche Centraalgebergte
- Laoet Tawar
- Ketol
- Takengon
- Blangkedjeren
- Singkel
- 1917
Source
De Buitenbezittingen, Deel II, Aflevering 1: Sumatra, Algemeene Hoofdstukken, bewerkt door het Encyclopaedisch Bureau, Mededeelingen van het Bureau voor de Bestuurszaken der Buitenbezittingen, Aflevering X (Weltevreden: Landsdrukkerij, 1917), Hoofdstuk I (Oro-hydrographisch), pp. 11, 27–28.