Landslides. Implementing the Proposed Project would result in increases in the volume of SWP water delivered to the Plaintiff Water Contractors and associated minor changes to existing SWP facility operations. No new construction or physical alteration of existing SWP facilities would occur. As discussed in Chapter 2, “Project Description,” implementing the Proposed Project would cause monthly water elevation fluctuations of up to 2 feet compared with existing conditions at Lake Oroville and San Luis Reservoir during certain water years. These minor changes could result in potential increases in the extent of exposed soil side slopes during periods of increased drawdown. This increased exposure has the potential to contribute to the activation of landslides or the reactivation of existing landslides; however, the drawdown of an additional 1 or 2 feet would be infrequent and would not change the existing drawdown rate. In addition, the minimum water surface elevation during existing operations would not be exceeded at Lake Oroville or San Luis Reservoir. No increase in the risk of sideslope landslides in Lake Oroville or San Luis Reservoir would occur. No impact would occur.
Landslides. Landslides are small to medium-sized movements that affect clays with gypsum and volcanic rocks dating to the Late Triassic (Xxxxxx). Xxxxxx outcroppings are predominantly on the northern face, linked to the detaching surfaces of the thrusts. They are fine-grained soils with low to medium plasticity, with effective cohesion values of around 0.4 Kp/cm2 and very low permeability values of around 1.8x10-6 cm/s (Xxxxxx et al., 2003; Xxxxxx et al., 2009). The landslides were mainly located on the northern face of the Tramuntana and they tend to be complex rotational landslides with mudflows at the bottom, that affected roadside-slopes with steep inclines (˃30º); in some cases they are reactivations of previous movements (Sa Calobra and Banyalbufar). Table 2 shows the characteristics of some of the landslides during the rainy period, and the figure 2 shows some photographs of the most important ones. They all affected the road network in the mountain range, primarily the Ma-10 road. The Estellencs landslide (Fig. 2-3) on the 8 March 2010 kept this road closed for three months, triggering numerous economic losses in the towns of Estellencs and Banyalbufar. Figure 1 Photographs of the most important dated rockfalls. 1) Puig Tomir (27/11/2008), 2) Son Cocó (19/12/2008), 3) Gorg Blau (31/12/2008), 4) Biniforani (5/01/2009), 5) Estellencs (15/01/2010) and 6) Son Antic (17/02/2010). The Gorg Blau rockfall cut off the Ma-10 road for 4 months. Figure 2 Photographs of the most important landslides recorded that affected the road network in the mountain range. 1) Sa Calobra (3/12/2008), 2) Cala Tuent (15/12/2008), 3) Estellencs (8/3/2010) and 4) Banyalbufar (9/5/2010). The Estellencs landslide cut off the Ma-10 road for 3 months. Table 1. Characteristics of the rockfalls dated during the period from October 2008 to February 2010 Rockfall Inventory No. Date Face Volume (m3) Altitude of failed massif (m) Runout (m) Type of failure (failure plane orientations) Lithology Puig Tomir Nº 30003 27/11/2008 N 16,000 620 350 Planar N30ºE Liassic limestone Son Cocó Nº 30008 19/12/2008 S 300,000 700 650 Wedge N30ºE N90ºE Liassic limestone Gorg Blau Nº 30009 31/12/2008 N 30,000 600 450 Wedge N30ºE N120ºE Liassic limestone Biniforani Nº 30013 5/01/2009 S 28,000 650 350 Wedge N30ºE N110ºE Liassic limestone Biniaraix Nº 30014 6/01/2009 N 3 600 100 planar N70ºE Liassic limestone Port de Valldemossa Nº 30015 07/01/2009 N 8 340 20 ¿? Liassic limestone Son Xxxxxxx Nº 30018 23/01/2009 N 10 200...
Landslides. Covered under this policy are damages deriving from moving land masses, rocks or other material of which adjacent properties are formed or on which the Insured’s buildings or installations are situated. COVERAGE D: NATURAL DISASTERS Covered under this policy are damages deriving from:
Landslides. It is known that large sections of the proposed route are in areas which have frequently experienced landslides. Much of the proposals developed within the existing Feasibility Study, dated 2008, in these areas involves cutting into soil and rock slopes. As such, the presence of this hazard (landslides) and its likelihood of occurrence, presents a major risk to the scheme. Section 3.2 of the existing Geotechnical Study, dated 2008, presents background information on the landslide areas. It is stated in the Feasibility Study that Sector I is not at risk from landslide. In Sector II, 721m (over seven sections) of known landslide has been identified, 518m of which are active. In Sector III, 613m (over five sections) of known landslides have been identified of which 412m are thought to be active. Cuttings affected include C48, C53, C54, C70, C71, C72 and C73. Embankments affected are E40, E56, E57, E58 and E59 (see Annex A to this Terms of Reference for list of cuttings, embankments and structures). Three structures are affected and these are S80, S86 and S116. The area around the Poiana Tunnel is also prone to landslides. The existing Geotechnical Study, dated 2008, recommends that monitoring of each potential landslide zone is carried out. The Consultant shall therefore implement a monitoring regime at each area of landslide identified. The purpose of this monitoring regime is to determine the nature of the instability (including ground movement and movements in groundwater level) in order to design appropriate stabilising measures. It is considered that landslides may be triggered by seasonal weather events (e.g. frost action, heavy rainfall and the like) and the monitoring regime must therefore be continuously implemented for a minimum of 12 months. The Consultant shall provide details of the intended frequency of monitoring within this 12 month period. It is expected that each Consultant shall propose a frequency of monitoring which will capture a sufficient quantity of data to properly assess the stability of the affected slopes. In addition, the Consultant shall determine the appropriate method of monitoring including type of instrumentation (e.g. piezometer, inclinometer and the like) and the means by which these instruments shall be observed and maintained. The Consultant shall also provide preliminary proposals for specific monitoring locations within the location of each slope. In addition to the areas of landslide and land instability, identified a...
Landslides
