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III. PHYSICAL INSPECTION ACTIVITIES <br />A. Introduction <br />The purpose of the source defect location and identification portion of the Sewer <br />System Evaluation Survey (SSES) is to locate extraneous water entering (leaking) <br />into the sanitary collection system and determine, through a cost efficient analysis, <br />a systematic approach of eliminating defects. The cost efficient analysis consists of <br />determining priority numbers for defects based on their estimated I/I contribution <br />divided by rehabilitation cost, thereby producing a priority ranking. Extraneous <br />water enters the system through various sources such as broken pipe, deteriorated <br />manholes, cracked service lines, and storm/sanitary collection system cross <br />connections. Source defect identification tasks determine the locations where <br />extraneous water enters the system. The source defect location methods used in <br />this study include: (1) visual manhole and pipe inspection, (2) smoke testing, (3) <br />dyed water flooding, and (4) internal television inspection. A summary of the <br />survey methods performed are listed in Table III-1, page III-3. <br />B. Source Defect Identification <br />Source defects are those defects or imperfections in the collection system which <br />allow either groundwater or storm water run-off to enter the collection system. The <br />location and severity of the defect determines the amount of I/I that enters the <br />system and the duration over which the extraneous flow affects the system. <br />The collection system defects are separated into two categories. The first, public <br />sector defects, are typically maintained by the municipality and include defects <br />found at manholes, on mainlines, and on municipal service lines. Manhole defects <br />include those found in the manhole structure. Examples of such defects include <br />leaks at the manhole cone joints and offset manhole frames. Mainline defects <br />include those found in the collection system mainlines. Examples of such defects <br />include cracks, offset joints, and faulty mainline taps. Municipal service defects <br />ADS Environmental Services, Inc. <br />III-1 <br />