ABSTRAK
The Bengawan Jero Irrigation Area (DI) includes the Bengawan Solo River Basin
which is located in the Lamongan Regency, East Java Province. During the rainy
season, the Rawa Geger area often inundates and experiences water shortages
during the dry season. So it is necessary to create a handling scenario for the
inundation that occurs.
To find out the condition of the Geger Swamp Area of Bengawan Jero, a
hydrological and hydraulics analysis was carried out in the canals around the
Geger Swamp Bengawan Jero where swelling often occurs. The data used in this
study consisted of Lamongan district rainfall data, inundation area data, and
topographical data using global mapper software. For the simulation of existing
conditions and handling scenarios using the Storm Water Management Model
(SWMM) software.
From the results of hydrological analysis, the distribution of rainfall uses a normal
distribution. Analysis of the runoff hydrograph from the catchment area using the
Hydrologic Engineering Center-Hydrology Modeling System (HAC-HMS) with a
period of 10 years obtained a flood discharge plan of 31.20 m3/s. The simulation
results of the existing conditions using the SWMM software show that all
channels are unable to accommodate flood discharge. So that the handling
scenario used is the construction of a retention pond with dimensions of a
retention pond with a pool length of 450 m, a pool width of 200 m, and a depth of
4 m, with 1 sluice gate with a door width of 0.8 m and a gate height of 1.5 m. In
addition, the channel improvement was also carried out by increasing the
dimensions of the channel so as to be able to channel the 10 year return period
flood discharge to the retention pond.
Swamp Geger, SWMM, retention pond