Causes, Effects, and Mitigation Measures of Time and Cost Overruns in Water Supply Projects: Case of Tigrai Region, Northern Ethiopia

Table 1

List of time and cost overrun factors [1, 6, 11, 17, 18, 20, 21, 23–25].

Nos	Factor description
	Causes of cost overrun	Causes of time overrun
I	Owner/consultant related
1	Late hand over of construction sites	Late hand over of construction sites
2	Late approval of design documents	Delay in progress payments
3	Change order	Delay in approval of shop drawings and samples
4	Faulty design documentation	Slow decision-making
5	Additional agreement	Change order
6	Client’s shortage of finance or delayed payments to contractors	Incomplete estimation of the project
7	Executive bureaucracy in the client’s organization	Additional agreement
8	Inadequate design supervision	Failure to choose appropriate contractor
9	Cost underestimation	The weakness of the consultant in terms of planning and supervising
10	Lack of sufficient experience of consultants	Lack of the consultant’s knowledge about the location of the project
11	Acceleration required by owner	Poor contract management of the owner/consultant
12	Need to update the design solutions as a result of technological progress
13	Mistakes and discrepancies in contract documents
II	Contractor related
14	Inexperienced contractor	Offering low price in tender
15	Failure to identify timely design and programming changes	Contractor’s financial difficulties
16	Contractor’s bankruptcy	Mistakes during construction and rework
17	Cost underestimation	Poor communication b/n contractor and other parties
18	Difficulties in finding construction materials in the local market	Ineffective planning and scheduling of projects by contractor
19	Poor communication b/n contractor and other parties	Improper construction methods
20	Mistakes during construction and rework	Delays in subcontractor’s work
		Insufficient delegation of power to the site management team
III	Project related
21	Complexity of construction projects	Complexity of construction projects
22	Size of project	Size of project
23	Location of project	Location of project
IV	Design related
24	Design errors and changes	Lack of consistency between bill of quantities and drawings
25	Lack of consistency between bill of quantities and drawings	Design errors and changes
		Poor specifications of materials
V	Material related
26	Shortage of materials and electromechanical equipment in local market	Shortage of construction materials and electromechanical equipment in market
27	Delay in material delivery	Delays in material import (pipes, fittings, etc.)
28	Inconstancy of the price of materials	Noncompliance of imported materials with the contract specifications
29	Inappropriate/misuse of material	Changes in material types and specifications during construction
30	Poor procurement programming of materials	Restrictions on issuing permits to transport material
VI	Equipment and labor related
31	Equipment availability and failure	Shortage of equipment and frequent breakdown
32	Low productivity and efficiency of equipment	Low productivity and efficiency of equipment
33	Fluctuation in the cost of labor	Lack of qualified production labors
34	Lack of qualified production labor
35	Weak motivation
VII	External factors
36	Inflation	Inflation
37	Severe weather conditions	Severe weather conditions
38	Unexpected ground conditions	Delay in obtaining permits and services from local authorities and other organizations such as electricity board
39	Changes in foreign exchange rate (for imported materials)	Changes in government laws and regulations
40	Effect of social and cultural factors	Force majeure (such as war, hostilities, riot, strike, political and economic instability, explosive materials, contamination, and earthquake)
41	Corruption
42	Fossils or discovery of things of geological or archaeological interest
43	Changes in government laws and regulations
44	Force majeure (such as war, terrorism, riot, strike, explosive materials, radiation, and earthquake)